Wrong value unsigned three #191

dileep-p · 2015-06-23T10:42:17Z

No description provided.

jmingov · 2015-06-23T20:50:25Z

@dileep-p this isnt the way to make a pull request into linux...

#17 (comment)

chest-rockwell · 2015-06-23T23:57:55Z

Also the "fix" is incorrect. See this pull request trying to merge the same bug.

dileep-p · 2015-06-24T07:44:37Z

Thanks for the info. Closing PR

commit 9cc6d9e upstream. Joachim Eastwood reports that commit fbfb872 "ARM: 8148/1: flush TLS and thumbee register state during exec" causes a boot-time crash on a Cortex-M4 nommu system: Freeing unused kernel memory: 68K (281e5000 - 281f6000) Unhandled exception: IPSR = 00000005 LR = fffffff1 CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 torvalds#191 task: 29834000 ti: 29832000 task.ti: 29832000 PC is at flush_thread+0x2e/0x40 LR is at flush_thread+0x21/0x40 pc : [<2800954a>] lr : [<2800953d>] psr: 4100000b sp : 29833d60 ip : 00000000 fp : 00000001 r10: 00003cf8 r9 : 29b1f000 r8 : 00000000 r7 : 29b0bc00 r6 : 29834000 r5 : 29832000 r4 : 29832000 r3 : ffff0ff0 r2 : 29832000 r1 : 00000000 r0 : 282121f0 xPSR: 4100000b CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 torvalds#191 [<2800afa5>] (unwind_backtrace) from [<2800a327>] (show_stack+0xb/0xc) [<2800a327>] (show_stack) from [<2800a963>] (__invalid_entry+0x4b/0x4c) The problem is that set_tls is attempting to clear the TLS location in the kernel-user helper page, which isn't set up on V7M. Fix this by guarding the write to the kuser helper page with a CONFIG_KUSER_HELPERS ifdef. Fixes: fbfb872 ARM: 8148/1: flush TLS and thumbee register state during exec Reported-by: Joachim Eastwood <[email protected]> Tested-by: Joachim Eastwood <[email protected]> Signed-off-by: Nathan Lynch <[email protected]> Signed-off-by: Russell King <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

This patch moves clk_get_rate() call from trigger() to hw_params() callback to avoid calling sleeping clk API from atomic context and prevent deadlock as indicated below. Before this change clk_get_rate() was being called with same spinlock held as the one passed to the clk API when registering clocks exposed by the I2S driver. [ 82.109780] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908 [ 82.117009] in_atomic(): 1, irqs_disabled(): 128, pid: 1554, name: speaker-test [ 82.124235] 3 locks held by speaker-test/1554: [ 82.128653] #0: cc8c5328 (snd_pcm_link_rwlock){...-}, at: snd_pcm_stream_lock_irq+0x20/0x38 [ 82.137058] #1: ec9eda17 (&(&substream->self_group.lock)->rlock){..-.}, at: snd_pcm_ioctl+0x900/0x1268 [ 82.146417] #2: 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4 [ 82.154650] irq event stamp: 8144 [ 82.157949] hardirqs last enabled at (8143): [<c0a0f574>] _raw_read_unlock_irq+0x24/0x5c [ 82.166089] hardirqs last disabled at (8144): [<c0a0f6a8>] _raw_read_lock_irq+0x18/0x58 [ 82.174063] softirqs last enabled at (8004): [<c01024e4>] __do_softirq+0x3a4/0x66c [ 82.181688] softirqs last disabled at (7997): [<c012d730>] irq_exit+0x140/0x168 [ 82.188964] Preemption disabled at: [ 82.188967] [<00000000>] (null) [ 82.195728] CPU: 6 PID: 1554 Comm: speaker-test Not tainted 5.0.0-rc5-00192-ga6e6caca8f03 torvalds#191 [ 82.204302] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 82.210376] [<c0111a54>] (unwind_backtrace) from [<c010d8f4>] (show_stack+0x10/0x14) [ 82.218084] [<c010d8f4>] (show_stack) from [<c09ef004>] (dump_stack+0x90/0xc8) [ 82.225278] [<c09ef004>] (dump_stack) from [<c0152980>] (___might_sleep+0x22c/0x2c8) [ 82.232990] [<c0152980>] (___might_sleep) from [<c0a0a2e4>] (__mutex_lock+0x28/0xa3c) [ 82.240788] [<c0a0a2e4>] (__mutex_lock) from [<c0a0ad80>] (mutex_lock_nested+0x1c/0x24) [ 82.248763] [<c0a0ad80>] (mutex_lock_nested) from [<c04923dc>] (clk_prepare_lock+0x78/0xec) [ 82.257079] [<c04923dc>] (clk_prepare_lock) from [<c049538c>] (clk_core_get_rate+0xc/0x5c) [ 82.265309] [<c049538c>] (clk_core_get_rate) from [<c0766b18>] (i2s_trigger+0x490/0x6d4) [ 82.273369] [<c0766b18>] (i2s_trigger) from [<c074fec4>] (soc_pcm_trigger+0x100/0x140) [ 82.281254] [<c074fec4>] (soc_pcm_trigger) from [<c07378a0>] (snd_pcm_do_start+0x2c/0x30) [ 82.289400] [<c07378a0>] (snd_pcm_do_start) from [<c07376cc>] (snd_pcm_action_single+0x38/0x78) [ 82.298065] [<c07376cc>] (snd_pcm_action_single) from [<c073a450>] (snd_pcm_ioctl+0x910/0x1268) [ 82.306734] [<c073a450>] (snd_pcm_ioctl) from [<c0292344>] (do_vfs_ioctl+0x90/0x9ec) [ 82.314443] [<c0292344>] (do_vfs_ioctl) from [<c0292cd4>] (ksys_ioctl+0x34/0x60) [ 82.321808] [<c0292cd4>] (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x28) [ 82.329431] Exception stack(0xeb875fa8 to 0xeb875ff0) [ 82.334459] 5fa0: 00033c18 b6e31000 00000004 00004142 00033d80 00033d80 [ 82.342605] 5fc0: 00033c18 b6e31000 00008000 00000036 00008000 00000000 beea38a8 00008000 [ 82.350748] 5fe0: b6e3142c beea384c b6da9a30 b6c9212c [ 82.355789] [ 82.357245] ====================================================== [ 82.363397] WARNING: possible circular locking dependency detected [ 82.369551] 5.0.0-rc5-00192-ga6e6caca8f03 torvalds#191 Tainted: G W [ 82.376395] ------------------------------------------------------ [ 82.382548] speaker-test/1554 is trying to acquire lock: [ 82.387834] 6d2007f4 (prepare_lock){+.+.}, at: clk_prepare_lock+0x78/0xec [ 82.394593] [ 82.394593] but task is already holding lock: [ 82.400398] 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4 [ 82.408197] [ 82.408197] which lock already depends on the new lock. [ 82.416343] [ 82.416343] the existing dependency chain (in reverse order) is: [ 82.423795] [ 82.423795] -> #1 (&(&pri_dai->spinlock)->rlock){..-.}: [ 82.430472] clk_mux_set_parent+0x34/0xb8 [ 82.434975] clk_core_set_parent_nolock+0x1c4/0x52c [ 82.440347] clk_set_parent+0x38/0x6c [ 82.444509] of_clk_set_defaults+0xc8/0x308 [ 82.449186] of_clk_add_provider+0x84/0xd0 [ 82.453779] samsung_i2s_probe+0x408/0x5f8 [ 82.458376] platform_drv_probe+0x48/0x98 [ 82.462879] really_probe+0x224/0x3f4 [ 82.467037] driver_probe_device+0x70/0x1c4 [ 82.471716] bus_for_each_drv+0x44/0x8c [ 82.476049] __device_attach+0xa0/0x138 [ 82.480382] bus_probe_device+0x88/0x90 [ 82.484715] deferred_probe_work_func+0x6c/0xbc [ 82.489741] process_one_work+0x200/0x740 [ 82.494246] worker_thread+0x2c/0x4c8 [ 82.498408] kthread+0x128/0x164 [ 82.502131] ret_from_fork+0x14/0x20 [ 82.506204] (null) [ 82.508976] [ 82.508976] -> #0 (prepare_lock){+.+.}: [ 82.514264] __mutex_lock+0x60/0xa3c [ 82.518336] mutex_lock_nested+0x1c/0x24 [ 82.522756] clk_prepare_lock+0x78/0xec [ 82.527088] clk_core_get_rate+0xc/0x5c [ 82.531421] i2s_trigger+0x490/0x6d4 [ 82.535494] soc_pcm_trigger+0x100/0x140 [ 82.539913] snd_pcm_do_start+0x2c/0x30 [ 82.544246] snd_pcm_action_single+0x38/0x78 [ 82.549012] snd_pcm_ioctl+0x910/0x1268 [ 82.553345] do_vfs_ioctl+0x90/0x9ec [ 82.557417] ksys_ioctl+0x34/0x60 [ 82.561229] ret_fast_syscall+0x0/0x28 [ 82.565477] 0xbeea384c [ 82.568421] [ 82.568421] other info that might help us debug this: [ 82.568421] [ 82.576394] Possible unsafe locking scenario: [ 82.576394] [ 82.582285] CPU0 CPU1 [ 82.586792] ---- ---- [ 82.591297] lock(&(&pri_dai->spinlock)->rlock); [ 82.595977] lock(prepare_lock); [ 82.601782] lock(&(&pri_dai->spinlock)->rlock); [ 82.608975] lock(prepare_lock); [ 82.612268] [ 82.612268] *** DEADLOCK *** Fixes: 647d04f ("ASoC: samsung: i2s: Ensure the RCLK rate is properly determined") Reported-by: Krzysztof Kozłowski <[email protected]> Signed-off-by: Sylwester Nawrocki <[email protected]> Signed-off-by: Mark Brown <[email protected]>

[ Upstream commit 860b454 ] This patch moves clk_get_rate() call from trigger() to hw_params() callback to avoid calling sleeping clk API from atomic context and prevent deadlock as indicated below. Before this change clk_get_rate() was being called with same spinlock held as the one passed to the clk API when registering clocks exposed by the I2S driver. [ 82.109780] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908 [ 82.117009] in_atomic(): 1, irqs_disabled(): 128, pid: 1554, name: speaker-test [ 82.124235] 3 locks held by speaker-test/1554: [ 82.128653] #0: cc8c5328 (snd_pcm_link_rwlock){...-}, at: snd_pcm_stream_lock_irq+0x20/0x38 [ 82.137058] #1: ec9eda17 (&(&substream->self_group.lock)->rlock){..-.}, at: snd_pcm_ioctl+0x900/0x1268 [ 82.146417] #2: 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4 [ 82.154650] irq event stamp: 8144 [ 82.157949] hardirqs last enabled at (8143): [<c0a0f574>] _raw_read_unlock_irq+0x24/0x5c [ 82.166089] hardirqs last disabled at (8144): [<c0a0f6a8>] _raw_read_lock_irq+0x18/0x58 [ 82.174063] softirqs last enabled at (8004): [<c01024e4>] __do_softirq+0x3a4/0x66c [ 82.181688] softirqs last disabled at (7997): [<c012d730>] irq_exit+0x140/0x168 [ 82.188964] Preemption disabled at: [ 82.188967] [<00000000>] (null) [ 82.195728] CPU: 6 PID: 1554 Comm: speaker-test Not tainted 5.0.0-rc5-00192-ga6e6caca8f03 #191 [ 82.204302] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 82.210376] [<c0111a54>] (unwind_backtrace) from [<c010d8f4>] (show_stack+0x10/0x14) [ 82.218084] [<c010d8f4>] (show_stack) from [<c09ef004>] (dump_stack+0x90/0xc8) [ 82.225278] [<c09ef004>] (dump_stack) from [<c0152980>] (___might_sleep+0x22c/0x2c8) [ 82.232990] [<c0152980>] (___might_sleep) from [<c0a0a2e4>] (__mutex_lock+0x28/0xa3c) [ 82.240788] [<c0a0a2e4>] (__mutex_lock) from [<c0a0ad80>] (mutex_lock_nested+0x1c/0x24) [ 82.248763] [<c0a0ad80>] (mutex_lock_nested) from [<c04923dc>] (clk_prepare_lock+0x78/0xec) [ 82.257079] [<c04923dc>] (clk_prepare_lock) from [<c049538c>] (clk_core_get_rate+0xc/0x5c) [ 82.265309] [<c049538c>] (clk_core_get_rate) from [<c0766b18>] (i2s_trigger+0x490/0x6d4) [ 82.273369] [<c0766b18>] (i2s_trigger) from [<c074fec4>] (soc_pcm_trigger+0x100/0x140) [ 82.281254] [<c074fec4>] (soc_pcm_trigger) from [<c07378a0>] (snd_pcm_do_start+0x2c/0x30) [ 82.289400] [<c07378a0>] (snd_pcm_do_start) from [<c07376cc>] (snd_pcm_action_single+0x38/0x78) [ 82.298065] [<c07376cc>] (snd_pcm_action_single) from [<c073a450>] (snd_pcm_ioctl+0x910/0x1268) [ 82.306734] [<c073a450>] (snd_pcm_ioctl) from [<c0292344>] (do_vfs_ioctl+0x90/0x9ec) [ 82.314443] [<c0292344>] (do_vfs_ioctl) from [<c0292cd4>] (ksys_ioctl+0x34/0x60) [ 82.321808] [<c0292cd4>] (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x28) [ 82.329431] Exception stack(0xeb875fa8 to 0xeb875ff0) [ 82.334459] 5fa0: 00033c18 b6e31000 00000004 00004142 00033d80 00033d80 [ 82.342605] 5fc0: 00033c18 b6e31000 00008000 00000036 00008000 00000000 beea38a8 00008000 [ 82.350748] 5fe0: b6e3142c beea384c b6da9a30 b6c9212c [ 82.355789] [ 82.357245] ====================================================== [ 82.363397] WARNING: possible circular locking dependency detected [ 82.369551] 5.0.0-rc5-00192-ga6e6caca8f03 #191 Tainted: G W [ 82.376395] ------------------------------------------------------ [ 82.382548] speaker-test/1554 is trying to acquire lock: [ 82.387834] 6d2007f4 (prepare_lock){+.+.}, at: clk_prepare_lock+0x78/0xec [ 82.394593] [ 82.394593] but task is already holding lock: [ 82.400398] 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4 [ 82.408197] [ 82.408197] which lock already depends on the new lock. [ 82.416343] [ 82.416343] the existing dependency chain (in reverse order) is: [ 82.423795] [ 82.423795] -> #1 (&(&pri_dai->spinlock)->rlock){..-.}: [ 82.430472] clk_mux_set_parent+0x34/0xb8 [ 82.434975] clk_core_set_parent_nolock+0x1c4/0x52c [ 82.440347] clk_set_parent+0x38/0x6c [ 82.444509] of_clk_set_defaults+0xc8/0x308 [ 82.449186] of_clk_add_provider+0x84/0xd0 [ 82.453779] samsung_i2s_probe+0x408/0x5f8 [ 82.458376] platform_drv_probe+0x48/0x98 [ 82.462879] really_probe+0x224/0x3f4 [ 82.467037] driver_probe_device+0x70/0x1c4 [ 82.471716] bus_for_each_drv+0x44/0x8c [ 82.476049] __device_attach+0xa0/0x138 [ 82.480382] bus_probe_device+0x88/0x90 [ 82.484715] deferred_probe_work_func+0x6c/0xbc [ 82.489741] process_one_work+0x200/0x740 [ 82.494246] worker_thread+0x2c/0x4c8 [ 82.498408] kthread+0x128/0x164 [ 82.502131] ret_from_fork+0x14/0x20 [ 82.506204] (null) [ 82.508976] [ 82.508976] -> #0 (prepare_lock){+.+.}: [ 82.514264] __mutex_lock+0x60/0xa3c [ 82.518336] mutex_lock_nested+0x1c/0x24 [ 82.522756] clk_prepare_lock+0x78/0xec [ 82.527088] clk_core_get_rate+0xc/0x5c [ 82.531421] i2s_trigger+0x490/0x6d4 [ 82.535494] soc_pcm_trigger+0x100/0x140 [ 82.539913] snd_pcm_do_start+0x2c/0x30 [ 82.544246] snd_pcm_action_single+0x38/0x78 [ 82.549012] snd_pcm_ioctl+0x910/0x1268 [ 82.553345] do_vfs_ioctl+0x90/0x9ec [ 82.557417] ksys_ioctl+0x34/0x60 [ 82.561229] ret_fast_syscall+0x0/0x28 [ 82.565477] 0xbeea384c [ 82.568421] [ 82.568421] other info that might help us debug this: [ 82.568421] [ 82.576394] Possible unsafe locking scenario: [ 82.576394] [ 82.582285] CPU0 CPU1 [ 82.586792] ---- ---- [ 82.591297] lock(&(&pri_dai->spinlock)->rlock); [ 82.595977] lock(prepare_lock); [ 82.601782] lock(&(&pri_dai->spinlock)->rlock); [ 82.608975] lock(prepare_lock); [ 82.612268] [ 82.612268] *** DEADLOCK *** Fixes: 647d04f ("ASoC: samsung: i2s: Ensure the RCLK rate is properly determined") Reported-by: Krzysztof Kozłowski <[email protected]> Signed-off-by: Sylwester Nawrocki <[email protected]> Signed-off-by: Mark Brown <[email protected]> Signed-off-by: Sasha Levin <[email protected]>

WARNING: Unknown commit id '70e806e4e645', maybe rebased or not pulled? #4: Since commit 70e806e ("mm: Do early cow for pinned pages during WARNING: Unknown commit id 'f3c64eda3e50', maybe rebased or not pulled? torvalds#34: problems (and was missing a barrrier), see commit f3c64ed ("mm: avoid WARNING: Unknown commit id 'f3c64eda3e50', maybe rebased or not pulled? torvalds#46: Fixes: f3c64ed ("mm: avoid early COW write protect games during fork()") WARNING: Prefer 'unsigned int' to bare use of 'unsigned' torvalds#136: FILE: mm/gup.c:2687: + unsigned seq; WARNING: Block comments should align the * on each line torvalds#191: FILE: mm/memory.c:1180: + * lockdep complaining about preemptibility. + */ total: 0 errors, 5 warnings, 109 lines checked NOTE: For some of the reported defects, checkpatch may be able to mechanically convert to the typical style using --fix or --fix-inplace. ./patches/mm-prevent-gup_fast-from-racing-with-cow-during-fork.patch has style problems, please review. NOTE: If any of the errors are false positives, please report them to the maintainer, see CHECKPATCH in MAINTAINERS. Please run checkpatch prior to sending patches Cc: Jason Gunthorpe <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

This patch moves clk_get_rate() call from trigger() to hw_params() callback to avoid calling sleeping clk API from atomic context and prevent deadlock as indicated below. Before this change clk_get_rate() was being called with same spinlock held as the one passed to the clk API when registering clocks exposed by the I2S driver. [ 82.109780] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908 [ 82.117009] in_atomic(): 1, irqs_disabled(): 128, pid: 1554, name: speaker-test [ 82.124235] 3 locks held by speaker-test/1554: [ 82.128653] #0: cc8c5328 (snd_pcm_link_rwlock){...-}, at: snd_pcm_stream_lock_irq+0x20/0x38 [ 82.137058] #1: ec9eda17 (&(&substream->self_group.lock)->rlock){..-.}, at: snd_pcm_ioctl+0x900/0x1268 [ 82.146417] #2: 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4 [ 82.154650] irq event stamp: 8144 [ 82.157949] hardirqs last enabled at (8143): [<c0a0f574>] _raw_read_unlock_irq+0x24/0x5c [ 82.166089] hardirqs last disabled at (8144): [<c0a0f6a8>] _raw_read_lock_irq+0x18/0x58 [ 82.174063] softirqs last enabled at (8004): [<c01024e4>] __do_softirq+0x3a4/0x66c [ 82.181688] softirqs last disabled at (7997): [<c012d730>] irq_exit+0x140/0x168 [ 82.188964] Preemption disabled at: [ 82.188967] [<00000000>] (null) [ 82.195728] CPU: 6 PID: 1554 Comm: speaker-test Not tainted 5.0.0-rc5-00192-ga6e6caca8f03 torvalds#191 [ 82.204302] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 82.210376] [<c0111a54>] (unwind_backtrace) from [<c010d8f4>] (show_stack+0x10/0x14) [ 82.218084] [<c010d8f4>] (show_stack) from [<c09ef004>] (dump_stack+0x90/0xc8) [ 82.225278] [<c09ef004>] (dump_stack) from [<c0152980>] (___might_sleep+0x22c/0x2c8) [ 82.232990] [<c0152980>] (___might_sleep) from [<c0a0a2e4>] (__mutex_lock+0x28/0xa3c) [ 82.240788] [<c0a0a2e4>] (__mutex_lock) from [<c0a0ad80>] (mutex_lock_nested+0x1c/0x24) [ 82.248763] [<c0a0ad80>] (mutex_lock_nested) from [<c04923dc>] (clk_prepare_lock+0x78/0xec) [ 82.257079] [<c04923dc>] (clk_prepare_lock) from [<c049538c>] (clk_core_get_rate+0xc/0x5c) [ 82.265309] [<c049538c>] (clk_core_get_rate) from [<c0766b18>] (i2s_trigger+0x490/0x6d4) [ 82.273369] [<c0766b18>] (i2s_trigger) from [<c074fec4>] (soc_pcm_trigger+0x100/0x140) [ 82.281254] [<c074fec4>] (soc_pcm_trigger) from [<c07378a0>] (snd_pcm_do_start+0x2c/0x30) [ 82.289400] [<c07378a0>] (snd_pcm_do_start) from [<c07376cc>] (snd_pcm_action_single+0x38/0x78) [ 82.298065] [<c07376cc>] (snd_pcm_action_single) from [<c073a450>] (snd_pcm_ioctl+0x910/0x1268) [ 82.306734] [<c073a450>] (snd_pcm_ioctl) from [<c0292344>] (do_vfs_ioctl+0x90/0x9ec) [ 82.314443] [<c0292344>] (do_vfs_ioctl) from [<c0292cd4>] (ksys_ioctl+0x34/0x60) [ 82.321808] [<c0292cd4>] (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x28) [ 82.329431] Exception stack(0xeb875fa8 to 0xeb875ff0) [ 82.334459] 5fa0: 00033c18 b6e31000 00000004 00004142 00033d80 00033d80 [ 82.342605] 5fc0: 00033c18 b6e31000 00008000 00000036 00008000 00000000 beea38a8 00008000 [ 82.350748] 5fe0: b6e3142c beea384c b6da9a30 b6c9212c [ 82.355789] [ 82.357245] ====================================================== [ 82.363397] WARNING: possible circular locking dependency detected [ 82.369551] 5.0.0-rc5-00192-ga6e6caca8f03 torvalds#191 Tainted: G W [ 82.376395] ------------------------------------------------------ [ 82.382548] speaker-test/1554 is trying to acquire lock: [ 82.387834] 6d2007f4 (prepare_lock){+.+.}, at: clk_prepare_lock+0x78/0xec [ 82.394593] [ 82.394593] but task is already holding lock: [ 82.400398] 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4 [ 82.408197] [ 82.408197] which lock already depends on the new lock. [ 82.416343] [ 82.416343] the existing dependency chain (in reverse order) is: [ 82.423795] [ 82.423795] -> #1 (&(&pri_dai->spinlock)->rlock){..-.}: [ 82.430472] clk_mux_set_parent+0x34/0xb8 [ 82.434975] clk_core_set_parent_nolock+0x1c4/0x52c [ 82.440347] clk_set_parent+0x38/0x6c [ 82.444509] of_clk_set_defaults+0xc8/0x308 [ 82.449186] of_clk_add_provider+0x84/0xd0 [ 82.453779] samsung_i2s_probe+0x408/0x5f8 [ 82.458376] platform_drv_probe+0x48/0x98 [ 82.462879] really_probe+0x224/0x3f4 [ 82.467037] driver_probe_device+0x70/0x1c4 [ 82.471716] bus_for_each_drv+0x44/0x8c [ 82.476049] __device_attach+0xa0/0x138 [ 82.480382] bus_probe_device+0x88/0x90 [ 82.484715] deferred_probe_work_func+0x6c/0xbc [ 82.489741] process_one_work+0x200/0x740 [ 82.494246] worker_thread+0x2c/0x4c8 [ 82.498408] kthread+0x128/0x164 [ 82.502131] ret_from_fork+0x14/0x20 [ 82.506204] (null) [ 82.508976] [ 82.508976] -> #0 (prepare_lock){+.+.}: [ 82.514264] __mutex_lock+0x60/0xa3c [ 82.518336] mutex_lock_nested+0x1c/0x24 [ 82.522756] clk_prepare_lock+0x78/0xec [ 82.527088] clk_core_get_rate+0xc/0x5c [ 82.531421] i2s_trigger+0x490/0x6d4 [ 82.535494] soc_pcm_trigger+0x100/0x140 [ 82.539913] snd_pcm_do_start+0x2c/0x30 [ 82.544246] snd_pcm_action_single+0x38/0x78 [ 82.549012] snd_pcm_ioctl+0x910/0x1268 [ 82.553345] do_vfs_ioctl+0x90/0x9ec [ 82.557417] ksys_ioctl+0x34/0x60 [ 82.561229] ret_fast_syscall+0x0/0x28 [ 82.565477] 0xbeea384c [ 82.568421] [ 82.568421] other info that might help us debug this: [ 82.568421] [ 82.576394] Possible unsafe locking scenario: [ 82.576394] [ 82.582285] CPU0 CPU1 [ 82.586792] ---- ---- [ 82.591297] lock(&(&pri_dai->spinlock)->rlock); [ 82.595977] lock(prepare_lock); [ 82.601782] lock(&(&pri_dai->spinlock)->rlock); [ 82.608975] lock(prepare_lock); [ 82.612268] [ 82.612268] *** DEADLOCK *** Fixes: 647d04f ("ASoC: samsung: i2s: Ensure the RCLK rate is properly determined") Reported-by: Krzysztof Kozłowski <[email protected]> Signed-off-by: Sylwester Nawrocki <[email protected]> Signed-off-by: Mark Brown <[email protected]>

WARNING: Unknown commit id '70e806e4e645', maybe rebased or not pulled? #4: Since commit 70e806e ("mm: Do early cow for pinned pages during WARNING: Unknown commit id 'f3c64eda3e50', maybe rebased or not pulled? torvalds#34: problems (and was missing a barrrier), see commit f3c64ed ("mm: avoid WARNING: Unknown commit id 'f3c64eda3e50', maybe rebased or not pulled? torvalds#46: Fixes: f3c64ed ("mm: avoid early COW write protect games during fork()") WARNING: Prefer 'unsigned int' to bare use of 'unsigned' torvalds#136: FILE: mm/gup.c:2687: + unsigned seq; WARNING: Block comments should align the * on each line torvalds#191: FILE: mm/memory.c:1180: + * lockdep complaining about preemptibility. + */ total: 0 errors, 5 warnings, 109 lines checked NOTE: For some of the reported defects, checkpatch may be able to mechanically convert to the typical style using --fix or --fix-inplace. ./patches/mm-prevent-gup_fast-from-racing-with-cow-during-fork.patch has style problems, please review. NOTE: If any of the errors are false positives, please report them to the maintainer, see CHECKPATCH in MAINTAINERS. Please run checkpatch prior to sending patches Cc: Jason Gunthorpe <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

…from plsdk-3113 to processor-sdk-linux-4.19.y * commit 'cf46e397a1b457ce2b31631a41b574fad9d0f4e7': clocksource: timer-ti-dm.c: fix merge error

Fix the following checkpatch errors: ERROR: "foo * bar" should be "foo *bar" torvalds#189: FILE: drivers/i2c/busses/i2c-amd8111.c:189: ERROR: "foo * bar" should be "foo *bar" torvalds#191: FILE: drivers/i2c/busses/i2c-amd8111.c:191: ERROR: switch and case should be at the same indent torvalds#201: FILE: drivers/i2c/busses/i2c-amd8111.c:201: ERROR: switch and case should be at the same indent torvalds#359: FILE: drivers/i2c/busses/i2c-amd8111.c:359: No functional changes. Signed-off-by: Tian Tao <[email protected]> Signed-off-by: Zihao Tang <[email protected]> Cc: Jean Delvare <[email protected]>

Move list implementation to `kernel` crate.

Fix the following checkpatch errors: ERROR: "foo * bar" should be "foo *bar" torvalds#189: FILE: drivers/i2c/busses/i2c-amd8111.c:189: ERROR: "foo * bar" should be "foo *bar" torvalds#191: FILE: drivers/i2c/busses/i2c-amd8111.c:191: ERROR: switch and case should be at the same indent torvalds#201: FILE: drivers/i2c/busses/i2c-amd8111.c:201: ERROR: switch and case should be at the same indent torvalds#359: FILE: drivers/i2c/busses/i2c-amd8111.c:359: No functional changes. Signed-off-by: Tian Tao <[email protected]> Signed-off-by: Zihao Tang <[email protected]> Signed-off-by: Wolfram Sang <[email protected]>

There are 2 mm_init functions in kernel. One in kernel/fork.c: static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, struct user_namespace *user_ns) And another one in init/main.c: static void __init mm_init(void) The BTF data will get the first one, which is most likely (in my case) mm_init from init/main.c without arguments. Then in runtime when we want to attach to 'mm_init' the kalsyms contains address of the one from kernel/fork.c. So we have function model with no arguments and using it to attach function with 3 arguments.. as result the trampoline will not save function's arguments and we get crash because trampoline changes argument registers: BUG: unable to handle page fault for address: 0000607d87a1d558 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 6 PID: 936 Comm: systemd Not tainted 5.12.0-rc4qemu+ torvalds#191 RIP: 0010:mm_init+0x223/0x2a0 ... Call Trace: ? bpf_trampoline_6442453476_0+0x3b/0x1000 dup_mm+0x66/0x5f0 ? __lock_task_sighand+0x3a/0x70 copy_process+0x17d0/0x1b50 kernel_clone+0x97/0x3c0 __do_sys_clone+0x60/0x80 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f1dc9b3201f I think there might be more cases like this, but I don't have an idea yet how to solve this in generic way. The rename in this change fix it for this instance. Signed-off-by: Jiri Olsa <[email protected]>

Note: squash with ("livepatch/selftests: add klp-convert") Fix the following checkpatch warnings: WARNING: externs should be avoided in .c files torvalds#66: FILE: lib/livepatch/test_klp_convert1.c:13: +extern char driver_name[]; WARNING: externs should be avoided in .c files torvalds#67: FILE: lib/livepatch/test_klp_convert1.c:14: +extern char homonym_string[]; WARNING: externs should be avoided in .c files torvalds#68: FILE: lib/livepatch/test_klp_convert1.c:15: +extern const char *get_homonym_string(void); WARNING: externs should be avoided in .c files torvalds#69: FILE: lib/livepatch/test_klp_convert1.c:16: +extern const char *test_klp_get_driver_name(void); WARNING: externs should be avoided in .c files torvalds#191: FILE: lib/livepatch/test_klp_convert2.c:13: +extern char driver_name[]; WARNING: externs should be avoided in .c files torvalds#192: FILE: lib/livepatch/test_klp_convert2.c:14: +extern char homonym_string[]; WARNING: externs should be avoided in .c files torvalds#193: FILE: lib/livepatch/test_klp_convert2.c:15: +extern const char *get_homonym_string(void); WARNING: externs should be avoided in .c files torvalds#194: FILE: lib/livepatch/test_klp_convert2.c:16: +extern const char *test_klp_get_driver_name(void); WARNING: externs should be avoided in .c files torvalds#30: FILE: lib/livepatch/test_klp_convert1.c:18: +extern char klp_string_a[] __asm__("klp_string.12345"); WARNING: externs should be avoided in .c files torvalds#31: FILE: lib/livepatch/test_klp_convert1.c:19: +extern char klp_string_b[] __asm__("klp_string.67890"); Signed-off-by: Joe Lawrence <[email protected]>

PD#150094: driver defect clean up: torvalds#32 torvalds#86 torvalds#90 torvalds#92 torvalds#97 torvalds#101 torvalds#103 torvalds#152 torvalds#155 torvalds#157~torvalds#158 torvalds#164 torvalds#167 torvalds#169~torvalds#179 torvalds#187~torvalds#191 torvalds#193~torvalds#199 torvalds#201~torvalds#210 torvalds#212~torvalds#213 torvalds#316~torvalds#319 torvalds#385 torvalds#572 torvalds#693~torvalds#694 torvalds#696~torvalds#697 Change-Id: I9669e5c0d717ee2287faf57a271ff27692039802 Signed-off-by: Guosong Zhou <[email protected]>

@0

Add tests that validate correctness and completeness of BPF verifier's register range bounds. The main bulk is a lot of auto-generated tests based on a small set of seed values for lower and upper 32 bits of full 64-bit values. Currently we validate only range vs const comparisons, but the idea is to start validating range over range comparisons in subsequent patch set. When setting up initial register ranges we treat registers as one of u64/s64/u32/s32 numeric types, and then independently perform conditional comparisons based on a potentially different u64/s64/u32/s32 types. This tests lots of tricky cases of deriving bounds information across different numeric domains. Given there are lots of auto-generated cases, we guard them behind SLOW_TESTS=1 envvar requirement, and skip them altogether otherwise. With current full set of upper/lower seed value, all supported comparison operators and all the combinations of u64/s64/u32/s32 number domains, we get about 7.7 million tests, which run in about 35 minutes on my local qemu instance. So it's something that can be run manually for exhaustive check in a reasonable time, and perhaps as a nightly CI test, but certainly is too slow to run as part of a default test_progs run. We also add a small set of tricky conditions that came up during development and triggered various bugs or corner cases in either selftest's reimplementation of range bounds logic or in verifier's logic itself. These are fast enough to be run as part of normal test_progs test run and are great for a quick sanity checking. Let's take a look at test output to understand what's going on: $ sudo ./test_progs -t reg_bounds_crafted torvalds#191/1 reg_bounds_crafted/(u64)[0; 0xffffffff] (u64)< 0:OK ... torvalds#191/115 reg_bounds_crafted/(u64)[0; 0x17fffffff] (s32)< 0:OK ... torvalds#191/137 reg_bounds_crafted/(u64)[0xffffffff; 0x100000000] (u64)== 0:OK Each test case is uniquely and fully described by this generated string. E.g.: "(u64)[0; 0x17fffffff] (s32)< 0". This means that we initialize a register (R6) in such a way that verifier knows that it can have a value in [(u64)0; (u64)0x17fffffff] range. Another register (R7) is also set up as u64, but this time a constant (zero in this case). They then are compared using 32-bit signed < operation. Resulting TRUE/FALSE branches are evaluated (including cases where it's known that one of the branches will never be taken, in which case we validate that verifier also determines this as a dead code). Test validates that verifier's final register state matches expected state based on selftest's own reg_state logic, implemented from scratch for cross-checking purposes. These test names can be conveniently used for further debugging, and if -vv verboseness is requested we can get a corresponding verifier log (with mark_precise logs filtered out as irrelevant and distracting). Example below is slightly redacted for brevity, omitting irrelevant register output in some places, marked with [...]. $ sudo ./test_progs -a 'reg_bounds_crafted/(u32)[0; U32_MAX] (s32)< -1' -vv ... VERIFIER LOG: ======================== func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (05) goto pc+2 3: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 4: (bc) w6 = w0 ; R0_w=scalar() R6_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 5: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 6: (bc) w7 = w0 ; R0_w=scalar() R7_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 7: (b4) w1 = 0 ; R1_w=0 8: (b4) w2 = -1 ; R2=4294967295 9: (ae) if w6 < w1 goto pc-9 9: R1=0 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 10: (2e) if w6 > w2 goto pc-10 10: R2=4294967295 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 11: (b4) w1 = -1 ; R1_w=4294967295 12: (b4) w2 = -1 ; R2_w=4294967295 13: (ae) if w7 < w1 goto pc-13 ; R1_w=4294967295 R7=4294967295 14: (2e) if w7 > w2 goto pc-14 14: R2_w=4294967295 R7=4294967295 15: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 16: (bc) w0 = w7 ; [...] R7=4294967295 17: (ce) if w6 s< w7 goto pc+3 ; R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) R7=4294967295 18: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) 19: (bc) w0 = w7 ; [...] R7=4294967295 20: (95) exit from 17 to 21: [...] 21: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=umin=umin32=2147483648,smax=umax=umax32=4294967294,smax32=-2,var_off=(0x80000000; 0x7fffffff)) 22: (bc) w0 = w7 ; [...] R7=4294967295 23: (95) exit from 13 to 1: [...] 1: [...] 1: (b7) r0 = 0 ; R0_w=0 2: (95) exit processed 24 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1 ===================== Verifier log above is for `(u32)[0; U32_MAX] (s32)< -1` use cases, where u32 range is used for initialization, followed by signed < operator. Note how we use w6/w7 in this case for register initialization (it would be R6/R7 for 64-bit types) and then `if w6 s< w7` for comparison at instruction torvalds#17. It will be `if R6 < R7` for 64-bit unsigned comparison. Above example gives a good impression of the overall structure of a BPF programs generated for reg_bounds tests. In the future, this "framework" can be extended to test not just conditional jumps, but also arithmetic operations. Adding randomized testing is another possibility. Some implementation notes. We basically have our own generics-like operations on numbers, where all the numbers are stored in u64, but how they are interpreted is passed as runtime argument enum num_t. Further, `struct range` represents a bounds range, and those are collected together into a minimal `struct reg_state`, which collects range bounds across all four numberical domains: u64, s64, u32, s64. Based on these primitives and `enum op` representing possible conditional operation (<, <=, >, >=, ==, !=), there is a set of generic helpers to perform "range arithmetics", which is used to maintain struct reg_state. We simulate what verifier will do for reg bounds of R6 and R7 registers using these range and reg_state primitives. Simulated information is used to determine branch taken conclusion and expected exact register state across all four number domains. Implementation of "range arithmetics" is more generic than what verifier is currently performing: it allows range over range comparisons and adjustments. This is the intended end goal of this work and verifier logic is expected to be enhanced to range vs range operations in subsequent patch set. Signed-off-by: Andrii Nakryiko <[email protected]>

@0

Add tests that validate correctness and completeness of BPF verifier's register range bounds. The main bulk is a lot of auto-generated tests based on a small set of seed values for lower and upper 32 bits of full 64-bit values. Currently we validate only range vs const comparisons, but the idea is to start validating range over range comparisons in subsequent patch set. When setting up initial register ranges we treat registers as one of u64/s64/u32/s32 numeric types, and then independently perform conditional comparisons based on a potentially different u64/s64/u32/s32 types. This tests lots of tricky cases of deriving bounds information across different numeric domains. Given there are lots of auto-generated cases, we guard them behind SLOW_TESTS=1 envvar requirement, and skip them altogether otherwise. With current full set of upper/lower seed value, all supported comparison operators and all the combinations of u64/s64/u32/s32 number domains, we get about 7.7 million tests, which run in about 35 minutes on my local qemu instance. So it's something that can be run manually for exhaustive check in a reasonable time, and perhaps as a nightly CI test, but certainly is too slow to run as part of a default test_progs run. We also add a small set of tricky conditions that came up during development and triggered various bugs or corner cases in either selftest's reimplementation of range bounds logic or in verifier's logic itself. These are fast enough to be run as part of normal test_progs test run and are great for a quick sanity checking. Let's take a look at test output to understand what's going on: $ sudo ./test_progs -t reg_bounds_crafted torvalds#191/1 reg_bounds_crafted/(u64)[0; 0xffffffff] (u64)< 0:OK ... torvalds#191/115 reg_bounds_crafted/(u64)[0; 0x17fffffff] (s32)< 0:OK ... torvalds#191/137 reg_bounds_crafted/(u64)[0xffffffff; 0x100000000] (u64)== 0:OK Each test case is uniquely and fully described by this generated string. E.g.: "(u64)[0; 0x17fffffff] (s32)< 0". This means that we initialize a register (R6) in such a way that verifier knows that it can have a value in [(u64)0; (u64)0x17fffffff] range. Another register (R7) is also set up as u64, but this time a constant (zero in this case). They then are compared using 32-bit signed < operation. Resulting TRUE/FALSE branches are evaluated (including cases where it's known that one of the branches will never be taken, in which case we validate that verifier also determines this as a dead code). Test validates that verifier's final register state matches expected state based on selftest's own reg_state logic, implemented from scratch for cross-checking purposes. These test names can be conveniently used for further debugging, and if -vv verboseness is requested we can get a corresponding verifier log (with mark_precise logs filtered out as irrelevant and distracting). Example below is slightly redacted for brevity, omitting irrelevant register output in some places, marked with [...]. $ sudo ./test_progs -a 'reg_bounds_crafted/(u32)[0; U32_MAX] (s32)< -1' -vv ... VERIFIER LOG: ======================== func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (05) goto pc+2 3: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 4: (bc) w6 = w0 ; R0_w=scalar() R6_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 5: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 6: (bc) w7 = w0 ; R0_w=scalar() R7_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 7: (b4) w1 = 0 ; R1_w=0 8: (b4) w2 = -1 ; R2=4294967295 9: (ae) if w6 < w1 goto pc-9 9: R1=0 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 10: (2e) if w6 > w2 goto pc-10 10: R2=4294967295 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 11: (b4) w1 = -1 ; R1_w=4294967295 12: (b4) w2 = -1 ; R2_w=4294967295 13: (ae) if w7 < w1 goto pc-13 ; R1_w=4294967295 R7=4294967295 14: (2e) if w7 > w2 goto pc-14 14: R2_w=4294967295 R7=4294967295 15: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 16: (bc) w0 = w7 ; [...] R7=4294967295 17: (ce) if w6 s< w7 goto pc+3 ; R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) R7=4294967295 18: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) 19: (bc) w0 = w7 ; [...] R7=4294967295 20: (95) exit from 17 to 21: [...] 21: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=umin=umin32=2147483648,smax=umax=umax32=4294967294,smax32=-2,var_off=(0x80000000; 0x7fffffff)) 22: (bc) w0 = w7 ; [...] R7=4294967295 23: (95) exit from 13 to 1: [...] 1: [...] 1: (b7) r0 = 0 ; R0_w=0 2: (95) exit processed 24 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1 ===================== Verifier log above is for `(u32)[0; U32_MAX] (s32)< -1` use cases, where u32 range is used for initialization, followed by signed < operator. Note how we use w6/w7 in this case for register initialization (it would be R6/R7 for 64-bit types) and then `if w6 s< w7` for comparison at instruction torvalds#17. It will be `if R6 < R7` for 64-bit unsigned comparison. Above example gives a good impression of the overall structure of a BPF programs generated for reg_bounds tests. In the future, this "framework" can be extended to test not just conditional jumps, but also arithmetic operations. Adding randomized testing is another possibility. Some implementation notes. We basically have our own generics-like operations on numbers, where all the numbers are stored in u64, but how they are interpreted is passed as runtime argument enum num_t. Further, `struct range` represents a bounds range, and those are collected together into a minimal `struct reg_state`, which collects range bounds across all four numberical domains: u64, s64, u32, s64. Based on these primitives and `enum op` representing possible conditional operation (<, <=, >, >=, ==, !=), there is a set of generic helpers to perform "range arithmetics", which is used to maintain struct reg_state. We simulate what verifier will do for reg bounds of R6 and R7 registers using these range and reg_state primitives. Simulated information is used to determine branch taken conclusion and expected exact register state across all four number domains. Implementation of "range arithmetics" is more generic than what verifier is currently performing: it allows range over range comparisons and adjustments. This is the intended end goal of this work and verifier logic is expected to be enhanced to range vs range operations in subsequent patch set. Signed-off-by: Andrii Nakryiko <[email protected]>

@0

Add test to validate BPF verifier's register range bounds tracking logic. The main bulk is a lot of auto-generated tests based on a small set of seed values for lower and upper 32 bits of full 64-bit values. Currently we validate only range vs const comparisons, but the idea is to start validating range over range comparisons in subsequent patch set. When setting up initial register ranges we treat registers as one of u64/s64/u32/s32 numeric types, and then independently perform conditional comparisons based on a potentially different u64/s64/u32/s32 types. This tests lots of tricky cases of deriving bounds information across different numeric domains. Given there are lots of auto-generated cases, we guard them behind SLOW_TESTS=1 envvar requirement, and skip them altogether otherwise. With current full set of upper/lower seed value, all supported comparison operators and all the combinations of u64/s64/u32/s32 number domains, we get about 7.7 million tests, which run in about 35 minutes on my local qemu instance. So it's something that can be run manually for exhaustive check in a reasonable time, and perhaps as a nightly CI test, but certainly is too slow to run as part of a default test_progs run. We also add a small set of tricky conditions that came up during development and triggered various bugs or corner cases in either selftest's reimplementation of range bounds logic or in verifier's logic itself. These are fast enough to be run as part of normal test_progs test run and are great for a quick sanity checking. Let's take a look at test output to understand what's going on: $ sudo ./test_progs -t reg_bounds_crafted torvalds#191/1 reg_bounds_crafted/(u64)[0; 0xffffffff] (u64)< 0:OK ... torvalds#191/115 reg_bounds_crafted/(u64)[0; 0x17fffffff] (s32)< 0:OK ... torvalds#191/137 reg_bounds_crafted/(u64)[0xffffffff; 0x100000000] (u64)== 0:OK Each test case is uniquely and fully described by this generated string. E.g.: "(u64)[0; 0x17fffffff] (s32)< 0". This means that we initialize a register (R6) in such a way that verifier knows that it can have a value in [(u64)0; (u64)0x17fffffff] range. Another register (R7) is also set up as u64, but this time a constant (zero in this case). They then are compared using 32-bit signed < operation. Resulting TRUE/FALSE branches are evaluated (including cases where it's known that one of the branches will never be taken, in which case we validate that verifier also determines this as a dead code). Test validates that verifier's final register state matches expected state based on selftest's own reg_state logic, implemented from scratch for cross-checking purposes. These test names can be conveniently used for further debugging, and if -vv verboseness is requested we can get a corresponding verifier log (with mark_precise logs filtered out as irrelevant and distracting). Example below is slightly redacted for brevity, omitting irrelevant register output in some places, marked with [...]. $ sudo ./test_progs -a 'reg_bounds_crafted/(u32)[0; U32_MAX] (s32)< -1' -vv ... VERIFIER LOG: ======================== func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (05) goto pc+2 3: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 4: (bc) w6 = w0 ; R0_w=scalar() R6_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 5: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 6: (bc) w7 = w0 ; R0_w=scalar() R7_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 7: (b4) w1 = 0 ; R1_w=0 8: (b4) w2 = -1 ; R2=4294967295 9: (ae) if w6 < w1 goto pc-9 9: R1=0 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 10: (2e) if w6 > w2 goto pc-10 10: R2=4294967295 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 11: (b4) w1 = -1 ; R1_w=4294967295 12: (b4) w2 = -1 ; R2_w=4294967295 13: (ae) if w7 < w1 goto pc-13 ; R1_w=4294967295 R7=4294967295 14: (2e) if w7 > w2 goto pc-14 14: R2_w=4294967295 R7=4294967295 15: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 16: (bc) w0 = w7 ; [...] R7=4294967295 17: (ce) if w6 s< w7 goto pc+3 ; R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) R7=4294967295 18: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) 19: (bc) w0 = w7 ; [...] R7=4294967295 20: (95) exit from 17 to 21: [...] 21: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=umin=umin32=2147483648,smax=umax=umax32=4294967294,smax32=-2,var_off=(0x80000000; 0x7fffffff)) 22: (bc) w0 = w7 ; [...] R7=4294967295 23: (95) exit from 13 to 1: [...] 1: [...] 1: (b7) r0 = 0 ; R0_w=0 2: (95) exit processed 24 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1 ===================== Verifier log above is for `(u32)[0; U32_MAX] (s32)< -1` use cases, where u32 range is used for initialization, followed by signed < operator. Note how we use w6/w7 in this case for register initialization (it would be R6/R7 for 64-bit types) and then `if w6 s< w7` for comparison at instruction torvalds#17. It will be `if R6 < R7` for 64-bit unsigned comparison. Above example gives a good impression of the overall structure of a BPF programs generated for reg_bounds tests. In the future, this "framework" can be extended to test not just conditional jumps, but also arithmetic operations. Adding randomized testing is another possibility. Some implementation notes. We basically have our own generics-like operations on numbers, where all the numbers are stored in u64, but how they are interpreted is passed as runtime argument enum num_t. Further, `struct range` represents a bounds range, and those are collected together into a minimal `struct reg_state`, which collects range bounds across all four numberical domains: u64, s64, u32, s64. Based on these primitives and `enum op` representing possible conditional operation (<, <=, >, >=, ==, !=), there is a set of generic helpers to perform "range arithmetics", which is used to maintain struct reg_state. We simulate what verifier will do for reg bounds of R6 and R7 registers using these range and reg_state primitives. Simulated information is used to determine branch taken conclusion and expected exact register state across all four number domains. Implementation of "range arithmetics" is more generic than what verifier is currently performing: it allows range over range comparisons and adjustments. This is the intended end goal of this work and verifier logic is expected to be enhanced to range vs range operations in subsequent patch set. Signed-off-by: Andrii Nakryiko <[email protected]>

@0

Add test to validate BPF verifier's register range bounds tracking logic. The main bulk is a lot of auto-generated tests based on a small set of seed values for lower and upper 32 bits of full 64-bit values. Currently we validate only range vs const comparisons, but the idea is to start validating range over range comparisons in subsequent patch set. When setting up initial register ranges we treat registers as one of u64/s64/u32/s32 numeric types, and then independently perform conditional comparisons based on a potentially different u64/s64/u32/s32 types. This tests lots of tricky cases of deriving bounds information across different numeric domains. Given there are lots of auto-generated cases, we guard them behind SLOW_TESTS=1 envvar requirement, and skip them altogether otherwise. With current full set of upper/lower seed value, all supported comparison operators and all the combinations of u64/s64/u32/s32 number domains, we get about 7.7 million tests, which run in about 35 minutes on my local qemu instance. So it's something that can be run manually for exhaustive check in a reasonable time, and perhaps as a nightly CI test, but certainly is too slow to run as part of a default test_progs run. We also add a small set of tricky conditions that came up during development and triggered various bugs or corner cases in either selftest's reimplementation of range bounds logic or in verifier's logic itself. These are fast enough to be run as part of normal test_progs test run and are great for a quick sanity checking. Let's take a look at test output to understand what's going on: $ sudo ./test_progs -t reg_bounds_crafted torvalds#191/1 reg_bounds_crafted/(u64)[0; 0xffffffff] (u64)< 0:OK ... torvalds#191/115 reg_bounds_crafted/(u64)[0; 0x17fffffff] (s32)< 0:OK ... torvalds#191/137 reg_bounds_crafted/(u64)[0xffffffff; 0x100000000] (u64)== 0:OK Each test case is uniquely and fully described by this generated string. E.g.: "(u64)[0; 0x17fffffff] (s32)< 0". This means that we initialize a register (R6) in such a way that verifier knows that it can have a value in [(u64)0; (u64)0x17fffffff] range. Another register (R7) is also set up as u64, but this time a constant (zero in this case). They then are compared using 32-bit signed < operation. Resulting TRUE/FALSE branches are evaluated (including cases where it's known that one of the branches will never be taken, in which case we validate that verifier also determines this as a dead code). Test validates that verifier's final register state matches expected state based on selftest's own reg_state logic, implemented from scratch for cross-checking purposes. These test names can be conveniently used for further debugging, and if -vv verboseness is requested we can get a corresponding verifier log (with mark_precise logs filtered out as irrelevant and distracting). Example below is slightly redacted for brevity, omitting irrelevant register output in some places, marked with [...]. $ sudo ./test_progs -a 'reg_bounds_crafted/(u32)[0; U32_MAX] (s32)< -1' -vv ... VERIFIER LOG: ======================== func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (05) goto pc+2 3: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 4: (bc) w6 = w0 ; R0_w=scalar() R6_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 5: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 6: (bc) w7 = w0 ; R0_w=scalar() R7_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 7: (b4) w1 = 0 ; R1_w=0 8: (b4) w2 = -1 ; R2=4294967295 9: (ae) if w6 < w1 goto pc-9 9: R1=0 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 10: (2e) if w6 > w2 goto pc-10 10: R2=4294967295 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 11: (b4) w1 = -1 ; R1_w=4294967295 12: (b4) w2 = -1 ; R2_w=4294967295 13: (ae) if w7 < w1 goto pc-13 ; R1_w=4294967295 R7=4294967295 14: (2e) if w7 > w2 goto pc-14 14: R2_w=4294967295 R7=4294967295 15: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 16: (bc) w0 = w7 ; [...] R7=4294967295 17: (ce) if w6 s< w7 goto pc+3 ; R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) R7=4294967295 18: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) 19: (bc) w0 = w7 ; [...] R7=4294967295 20: (95) exit from 17 to 21: [...] 21: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=umin=umin32=2147483648,smax=umax=umax32=4294967294,smax32=-2,var_off=(0x80000000; 0x7fffffff)) 22: (bc) w0 = w7 ; [...] R7=4294967295 23: (95) exit from 13 to 1: [...] 1: [...] 1: (b7) r0 = 0 ; R0_w=0 2: (95) exit processed 24 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1 ===================== Verifier log above is for `(u32)[0; U32_MAX] (s32)< -1` use cases, where u32 range is used for initialization, followed by signed < operator. Note how we use w6/w7 in this case for register initialization (it would be R6/R7 for 64-bit types) and then `if w6 s< w7` for comparison at instruction torvalds#17. It will be `if R6 < R7` for 64-bit unsigned comparison. Above example gives a good impression of the overall structure of a BPF programs generated for reg_bounds tests. In the future, this "framework" can be extended to test not just conditional jumps, but also arithmetic operations. Adding randomized testing is another possibility. Some implementation notes. We basically have our own generics-like operations on numbers, where all the numbers are stored in u64, but how they are interpreted is passed as runtime argument enum num_t. Further, `struct range` represents a bounds range, and those are collected together into a minimal `struct reg_state`, which collects range bounds across all four numberical domains: u64, s64, u32, s64. Based on these primitives and `enum op` representing possible conditional operation (<, <=, >, >=, ==, !=), there is a set of generic helpers to perform "range arithmetics", which is used to maintain struct reg_state. We simulate what verifier will do for reg bounds of R6 and R7 registers using these range and reg_state primitives. Simulated information is used to determine branch taken conclusion and expected exact register state across all four number domains. Implementation of "range arithmetics" is more generic than what verifier is currently performing: it allows range over range comparisons and adjustments. This is the intended end goal of this work and verifier logic is expected to be enhanced to range vs range operations in subsequent patch set. Signed-off-by: Andrii Nakryiko <[email protected]>

@0

Add test to validate BPF verifier's register range bounds tracking logic. The main bulk is a lot of auto-generated tests based on a small set of seed values for lower and upper 32 bits of full 64-bit values. Currently we validate only range vs const comparisons, but the idea is to start validating range over range comparisons in subsequent patch set. When setting up initial register ranges we treat registers as one of u64/s64/u32/s32 numeric types, and then independently perform conditional comparisons based on a potentially different u64/s64/u32/s32 types. This tests lots of tricky cases of deriving bounds information across different numeric domains. Given there are lots of auto-generated cases, we guard them behind SLOW_TESTS=1 envvar requirement, and skip them altogether otherwise. With current full set of upper/lower seed value, all supported comparison operators and all the combinations of u64/s64/u32/s32 number domains, we get about 7.7 million tests, which run in about 35 minutes on my local qemu instance without parallelization. But we also split those tests by init/cond numeric types, which allows to rely on test_progs's parallelization of tests with `-j` option, getting run time down to about 5 minutes on 8 cores. It's still something that shouldn't be run during normal test_progs run. But we can run it a reasonable time, and so perhaps a nightly CI test run (once we have it) would be a good option for this. We also add a small set of tricky conditions that came up during development and triggered various bugs or corner cases in either selftest's reimplementation of range bounds logic or in verifier's logic itself. These are fast enough to be run as part of normal test_progs test run and are great for a quick sanity checking. Let's take a look at test output to understand what's going on: $ sudo ./test_progs -t reg_bounds_crafted torvalds#191/1 reg_bounds_crafted/(u64)[0; 0xffffffff] (u64)< 0:OK ... torvalds#191/115 reg_bounds_crafted/(u64)[0; 0x17fffffff] (s32)< 0:OK ... torvalds#191/137 reg_bounds_crafted/(u64)[0xffffffff; 0x100000000] (u64)== 0:OK Each test case is uniquely and fully described by this generated string. E.g.: "(u64)[0; 0x17fffffff] (s32)< 0". This means that we initialize a register (R6) in such a way that verifier knows that it can have a value in [(u64)0; (u64)0x17fffffff] range. Another register (R7) is also set up as u64, but this time a constant (zero in this case). They then are compared using 32-bit signed < operation. Resulting TRUE/FALSE branches are evaluated (including cases where it's known that one of the branches will never be taken, in which case we validate that verifier also determines this as a dead code). Test validates that verifier's final register state matches expected state based on selftest's own reg_state logic, implemented from scratch for cross-checking purposes. These test names can be conveniently used for further debugging, and if -vv verboseness is requested we can get a corresponding verifier log (with mark_precise logs filtered out as irrelevant and distracting). Example below is slightly redacted for brevity, omitting irrelevant register output in some places, marked with [...]. $ sudo ./test_progs -a 'reg_bounds_crafted/(u32)[0; U32_MAX] (s32)< -1' -vv ... VERIFIER LOG: ======================== func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (05) goto pc+2 3: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 4: (bc) w6 = w0 ; R0_w=scalar() R6_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 5: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 6: (bc) w7 = w0 ; R0_w=scalar() R7_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 7: (b4) w1 = 0 ; R1_w=0 8: (b4) w2 = -1 ; R2=4294967295 9: (ae) if w6 < w1 goto pc-9 9: R1=0 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 10: (2e) if w6 > w2 goto pc-10 10: R2=4294967295 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 11: (b4) w1 = -1 ; R1_w=4294967295 12: (b4) w2 = -1 ; R2_w=4294967295 13: (ae) if w7 < w1 goto pc-13 ; R1_w=4294967295 R7=4294967295 14: (2e) if w7 > w2 goto pc-14 14: R2_w=4294967295 R7=4294967295 15: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 16: (bc) w0 = w7 ; [...] R7=4294967295 17: (ce) if w6 s< w7 goto pc+3 ; R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) R7=4294967295 18: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) 19: (bc) w0 = w7 ; [...] R7=4294967295 20: (95) exit from 17 to 21: [...] 21: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=umin=umin32=2147483648,smax=umax=umax32=4294967294,smax32=-2,var_off=(0x80000000; 0x7fffffff)) 22: (bc) w0 = w7 ; [...] R7=4294967295 23: (95) exit from 13 to 1: [...] 1: [...] 1: (b7) r0 = 0 ; R0_w=0 2: (95) exit processed 24 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1 ===================== Verifier log above is for `(u32)[0; U32_MAX] (s32)< -1` use cases, where u32 range is used for initialization, followed by signed < operator. Note how we use w6/w7 in this case for register initialization (it would be R6/R7 for 64-bit types) and then `if w6 s< w7` for comparison at instruction torvalds#17. It will be `if R6 < R7` for 64-bit unsigned comparison. Above example gives a good impression of the overall structure of a BPF programs generated for reg_bounds tests. In the future, this "framework" can be extended to test not just conditional jumps, but also arithmetic operations. Adding randomized testing is another possibility. Some implementation notes. We basically have our own generics-like operations on numbers, where all the numbers are stored in u64, but how they are interpreted is passed as runtime argument enum num_t. Further, `struct range` represents a bounds range, and those are collected together into a minimal `struct reg_state`, which collects range bounds across all four numberical domains: u64, s64, u32, s64. Based on these primitives and `enum op` representing possible conditional operation (<, <=, >, >=, ==, !=), there is a set of generic helpers to perform "range arithmetics", which is used to maintain struct reg_state. We simulate what verifier will do for reg bounds of R6 and R7 registers using these range and reg_state primitives. Simulated information is used to determine branch taken conclusion and expected exact register state across all four number domains. Implementation of "range arithmetics" is more generic than what verifier is currently performing: it allows range over range comparisons and adjustments. This is the intended end goal of this patch set overall and verifier logic is enhanced in subsequent patches in this series to handle range vs range operations, at which point selftests are extended to validate these conditions as well. For now it's range vs const cases only. Note that tests are split into multiple groups by their numeric types for initialization of ranges and for comparison operation. This allows to use test_progs's -j parallelization to speed up tests, as we now have 16 groups of parallel running tests. Overall reduction of running time that allows is pretty good, we go down from more than 30 minutes to slightly less than 5 minutes running time. Signed-off-by: Andrii Nakryiko <[email protected]>

@0

Add test to validate BPF verifier's register range bounds tracking logic. The main bulk is a lot of auto-generated tests based on a small set of seed values for lower and upper 32 bits of full 64-bit values. Currently we validate only range vs const comparisons, but the idea is to start validating range over range comparisons in subsequent patch set. When setting up initial register ranges we treat registers as one of u64/s64/u32/s32 numeric types, and then independently perform conditional comparisons based on a potentially different u64/s64/u32/s32 types. This tests lots of tricky cases of deriving bounds information across different numeric domains. Given there are lots of auto-generated cases, we guard them behind SLOW_TESTS=1 envvar requirement, and skip them altogether otherwise. With current full set of upper/lower seed value, all supported comparison operators and all the combinations of u64/s64/u32/s32 number domains, we get about 7.7 million tests, which run in about 35 minutes on my local qemu instance without parallelization. But we also split those tests by init/cond numeric types, which allows to rely on test_progs's parallelization of tests with `-j` option, getting run time down to about 5 minutes on 8 cores. It's still something that shouldn't be run during normal test_progs run. But we can run it a reasonable time, and so perhaps a nightly CI test run (once we have it) would be a good option for this. We also add a small set of tricky conditions that came up during development and triggered various bugs or corner cases in either selftest's reimplementation of range bounds logic or in verifier's logic itself. These are fast enough to be run as part of normal test_progs test run and are great for a quick sanity checking. Let's take a look at test output to understand what's going on: $ sudo ./test_progs -t reg_bounds_crafted torvalds#191/1 reg_bounds_crafted/(u64)[0; 0xffffffff] (u64)< 0:OK ... torvalds#191/115 reg_bounds_crafted/(u64)[0; 0x17fffffff] (s32)< 0:OK ... torvalds#191/137 reg_bounds_crafted/(u64)[0xffffffff; 0x100000000] (u64)== 0:OK Each test case is uniquely and fully described by this generated string. E.g.: "(u64)[0; 0x17fffffff] (s32)< 0". This means that we initialize a register (R6) in such a way that verifier knows that it can have a value in [(u64)0; (u64)0x17fffffff] range. Another register (R7) is also set up as u64, but this time a constant (zero in this case). They then are compared using 32-bit signed < operation. Resulting TRUE/FALSE branches are evaluated (including cases where it's known that one of the branches will never be taken, in which case we validate that verifier also determines this as a dead code). Test validates that verifier's final register state matches expected state based on selftest's own reg_state logic, implemented from scratch for cross-checking purposes. These test names can be conveniently used for further debugging, and if -vv verboseness is requested we can get a corresponding verifier log (with mark_precise logs filtered out as irrelevant and distracting). Example below is slightly redacted for brevity, omitting irrelevant register output in some places, marked with [...]. $ sudo ./test_progs -a 'reg_bounds_crafted/(u32)[0; U32_MAX] (s32)< -1' -vv ... VERIFIER LOG: ======================== func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (05) goto pc+2 3: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 4: (bc) w6 = w0 ; R0_w=scalar() R6_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 5: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar() 6: (bc) w7 = w0 ; R0_w=scalar() R7_w=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 7: (b4) w1 = 0 ; R1_w=0 8: (b4) w2 = -1 ; R2=4294967295 9: (ae) if w6 < w1 goto pc-9 9: R1=0 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 10: (2e) if w6 > w2 goto pc-10 10: R2=4294967295 R6=scalar(smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 11: (b4) w1 = -1 ; R1_w=4294967295 12: (b4) w2 = -1 ; R2_w=4294967295 13: (ae) if w7 < w1 goto pc-13 ; R1_w=4294967295 R7=4294967295 14: (2e) if w7 > w2 goto pc-14 14: R2_w=4294967295 R7=4294967295 15: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,var_off=(0x0; 0xffffffff)) 16: (bc) w0 = w7 ; [...] R7=4294967295 17: (ce) if w6 s< w7 goto pc+3 ; R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) R7=4294967295 18: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=0,smax=umax=4294967295,smin32=-1,var_off=(0x0; 0xffffffff)) 19: (bc) w0 = w7 ; [...] R7=4294967295 20: (95) exit from 17 to 21: [...] 21: (bc) w0 = w6 ; [...] R6=scalar(id=1,smin=umin=umin32=2147483648,smax=umax=umax32=4294967294,smax32=-2,var_off=(0x80000000; 0x7fffffff)) 22: (bc) w0 = w7 ; [...] R7=4294967295 23: (95) exit from 13 to 1: [...] 1: [...] 1: (b7) r0 = 0 ; R0_w=0 2: (95) exit processed 24 insns (limit 1000000) max_states_per_insn 0 total_states 2 peak_states 2 mark_read 1 ===================== Verifier log above is for `(u32)[0; U32_MAX] (s32)< -1` use cases, where u32 range is used for initialization, followed by signed < operator. Note how we use w6/w7 in this case for register initialization (it would be R6/R7 for 64-bit types) and then `if w6 s< w7` for comparison at instruction torvalds#17. It will be `if R6 < R7` for 64-bit unsigned comparison. Above example gives a good impression of the overall structure of a BPF programs generated for reg_bounds tests. In the future, this "framework" can be extended to test not just conditional jumps, but also arithmetic operations. Adding randomized testing is another possibility. Some implementation notes. We basically have our own generics-like operations on numbers, where all the numbers are stored in u64, but how they are interpreted is passed as runtime argument enum num_t. Further, `struct range` represents a bounds range, and those are collected together into a minimal `struct reg_state`, which collects range bounds across all four numberical domains: u64, s64, u32, s64. Based on these primitives and `enum op` representing possible conditional operation (<, <=, >, >=, ==, !=), there is a set of generic helpers to perform "range arithmetics", which is used to maintain struct reg_state. We simulate what verifier will do for reg bounds of R6 and R7 registers using these range and reg_state primitives. Simulated information is used to determine branch taken conclusion and expected exact register state across all four number domains. Implementation of "range arithmetics" is more generic than what verifier is currently performing: it allows range over range comparisons and adjustments. This is the intended end goal of this patch set overall and verifier logic is enhanced in subsequent patches in this series to handle range vs range operations, at which point selftests are extended to validate these conditions as well. For now it's range vs const cases only. Note that tests are split into multiple groups by their numeric types for initialization of ranges and for comparison operation. This allows to use test_progs's -j parallelization to speed up tests, as we now have 16 groups of parallel running tests. Overall reduction of running time that allows is pretty good, we go down from more than 30 minutes to slightly less than 5 minutes running time. Acked-by: Eduard Zingerman <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Acked-by: Shung-Hsi Yu <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>

hwmon: (emc2305) add support for EMC2301/2/3/5 RPM-based PWM Fan Spee…

Wrong value unsigned three

0fb23e4

dileep-p closed this Jun 24, 2015

laijs pushed a commit to laijs/linux that referenced this pull request Feb 13, 2017

Merge pull request torvalds#191 from libos-nuse/fix-tap-offload

28ce8a3

ojeda added a commit to ojeda/linux that referenced this pull request Apr 14, 2021

Merge pull request torvalds#191 from wedsonaf/list

87e3dee

Move list implementation to `kernel` crate.

RadxaStephen pushed a commit to RadxaStephen/linux that referenced this pull request Mar 6, 2024

Merge pull request torvalds#191 from nascs/Radxa_cm3_rpi_cm4_io_emc2305

22d04b0

hwmon: (emc2305) add support for EMC2301/2/3/5 RPM-based PWM Fan Spee…

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Wrong value unsigned three #191

Wrong value unsigned three #191

dileep-p commented Jun 23, 2015

jmingov commented Jun 23, 2015

chest-rockwell commented Jun 23, 2015

dileep-p commented Jun 24, 2015

Wrong value unsigned three #191

Wrong value unsigned three #191

Conversation

dileep-p commented Jun 23, 2015

jmingov commented Jun 23, 2015

chest-rockwell commented Jun 23, 2015

dileep-p commented Jun 24, 2015