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gpu/drm: hisilicon patchset addressing display issues #8

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merged 7 commits into from
Mar 6, 2015
Merged

gpu/drm: hisilicon patchset addressing display issues #8

merged 7 commits into from
Mar 6, 2015

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@ldts ldts commented Mar 5, 2015

This patch set enables the ADV7533 HDMI encoder device and fixes display issues.

[Pull request created to allow review]

Xinliang Liu and others added 7 commits March 5, 2015 13:13
The drm_get_edid() function performs direct I2C accesses to read EDID
blocks, assuming that the monitor DDC interface is directly connected to
the I2C bus. It can't thus be used with HDMI encoders that control the
DDC bus and expose EDID blocks through a different interface.

Refactor drm_do_get_edid() to take a block read callback function
instead of an I2C adapter, and export it for direct use by drivers.

As in the general case the DDC bus is accessible by the kernel at the
I2C level, drivers must make all reasonable efforts to expose it as an
I2C adapter and use drm_get_edid() instead of abusing this function.

Signed-off-by: Lars-Peter Clausen <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>
Reviewed-by: Rob Clark <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>

Conflicts:
	include/drm/drm_edid.h
use a adv private get_edid_block function
fboudra added a commit that referenced this pull request Mar 6, 2015
gpu/drm: hisilicon patchset addressing display issues
@fboudra fboudra merged commit 7bfade6 into 96boards:hikey Mar 6, 2015
koenkooi pushed a commit that referenced this pull request Mar 10, 2015
Currently we're getting IRQs after lots of resources are already
allocated:
 * netdev
 * clocks
 * MDIO bus
Also HW gets initialized by the time when checking IRQs as well.

Now there's a possibility for master interrupt controller to be not
probed yet. This will lead to exit from GMAC probe routine with "-
EPROBE_DEFER" and so deferred probe will hapen later on.

But since we exited the first GMAC probe without release of all
allocated resources there could be conflicts on subsequent probes.

For example this is what happens for me:
 --->8---
 stmmaceth e0018000.ethernet: no reset control found
 stmmac - user ID: 0x10, Synopsys ID: 0x37
  Ring mode enabled
  DMA HW capability register supported
  Normal descriptors
  RX Checksum Offload Engine supported (type 2)
  TX Checksum insertion supported
  Enable RX Mitigation via HW Watchdog Timer
 libphy: stmmac: probed
 eth0: PHY ID 20005c7a at 1 IRQ POLL (stmmac-0:01) active
 platform e0018000.ethernet: Driver stmmaceth requests probe deferral
 ...
 ...
 ...
 stmmaceth e0018000.ethernet: no reset control found
 stmmac - user ID: 0x10, Synopsys ID: 0x37
  Ring mode enabled
  DMA HW capability register supported
  Normal descriptors
  RX Checksum Offload Engine supported (type 2)
  TX Checksum insertion supported
  Enable RX Mitigation via HW Watchdog Timer
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 6 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x4e/0x68()
 sysfs: cannot create duplicate filename
'/devices/platform/axs10x_mb/e0018000.ethernet/mdio_bus/stmmac-0'
 CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 4.0.0-rc1-next-20150303+#8
 Workqueue: deferwq deferred_probe_work_func

 Stack Trace:
  arc_unwind_core+0xb8/0x114
  warn_slowpath_common+0x5a/0x8c
  warn_slowpath_fmt+0x2e/0x38
  sysfs_warn_dup+0x4e/0x68
  sysfs_create_dir_ns+0x98/0xa0
  kobject_add_internal+0x8c/0x2e8
  kobject_add+0x4a/0x8c
  device_add+0xc6/0x448
  mdiobus_register+0x6c/0x164
  stmmac_mdio_register+0x112/0x264
  stmmac_dvr_probe+0x6c0/0x85c
  stmmac_pltfr_probe+0x2e4/0x50c
  platform_drv_probe+0x26/0x5c
  really_probe+0x76/0x1dc
  bus_for_each_drv+0x42/0x7c
  device_attach+0x64/0x6c
  bus_probe_device+0x74/0xa4
  deferred_probe_work_func+0x50/0x84
  process_one_work+0xf8/0x2cc
  worker_thread+0x110/0x478
  kthread+0x8a/0x9c
  ret_from_fork+0x14/0x18
 ---[ end trace a2dfaa7d630c8be1 ]---
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 6 at lib/kobject.c:240
kobject_add_internal+0x218/0x2e8()
 kobject_add_internal failed for stmmac-0 with -EEXIST, don't try to
register things with the same name in the same di.
 CPU: 0 PID: 6 Comm: kworker/u2:0 Tainted: G        W
4.0.0-rc1-next-20150303+ #8
 Workqueue: deferwq deferred_probe_work_func

 Stack Trace:
  arc_unwind_core+0xb8/0x114
  warn_slowpath_common+0x5a/0x8c
  warn_slowpath_fmt+0x2e/0x38
  kobject_add_internal+0x218/0x2e8
  kobject_add+0x4a/0x8c
  device_add+0xc6/0x448
  mdiobus_register+0x6c/0x164
  stmmac_mdio_register+0x112/0x264
  stmmac_dvr_probe+0x6c0/0x85c
  stmmac_pltfr_probe+0x2e4/0x50c
  platform_drv_probe+0x26/0x5c
  really_probe+0x76/0x1dc
  bus_for_each_drv+0x42/0x7c
  device_attach+0x64/0x6c
  bus_probe_device+0x74/0xa4
  deferred_probe_work_func+0x50/0x84
  process_one_work+0xf8/0x2cc
  worker_thread+0x110/0x478
  kthread+0x8a/0x9c
  ret_from_fork+0x14/0x18
 ---[ end trace a2dfaa7d630c8be2 ]---
 libphy: mii_bus stmmac-0 failed to register
 : Cannot register as MDIO bus
 stmmac_pltfr_probe: main driver probe failed
 stmmaceth: probe of e0018000.ethernet failed with error -22
 --->8---

Essential fix is to check for IRQs availability as early as possible and
then safely go to deferred probe if IRQs are not there yet.

Signed-off-by: Alexey Brodkin <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Giuseppe Cavallaro <[email protected]>
Cc: Sonic Zhang <[email protected]>
Cc: David S. Miller <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
docularxu added a commit that referenced this pull request Mar 16, 2015
Add a u32 in struct wl1271 to make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
docularxu added a commit that referenced this pull request Mar 25, 2015
Add a u32 in struct wl1271 to make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
koenkooi pushed a commit that referenced this pull request Apr 1, 2015
Commit 9aabf81 ("mm/slub: optimize alloc/free fastpath by removing
preemption on/off") introduced an occasional hang for kernels built with
CONFIG_PREEMPT && !CONFIG_SMP.

The problem is the following loop the patch introduced to
slab_alloc_node and slab_free:

    do {
        tid = this_cpu_read(s->cpu_slab->tid);
        c = raw_cpu_ptr(s->cpu_slab);
    } while (IS_ENABLED(CONFIG_PREEMPT) && unlikely(tid != c->tid));

GCC 4.9 has been observed to hoist the load of c and c->tid above the
loop for !SMP kernels (as in this case raw_cpu_ptr(x) is compile-time
constant and does not force a reload).  On arm64 the generated assembly
looks like:

         ldr     x4, [x0,#8]
  loop:
         ldr     x1, [x0,#8]
         cmp     x1, x4
         b.ne    loop

If the thread is preempted between the load of c->tid (into x1) and tid
(into x4), and an allocation or free occurs in another thread (bumping
the cpu_slab's tid), the thread will be stuck in the loop until
s->cpu_slab->tid wraps, which may be forever in the absence of
allocations/frees on the same CPU.

This patch changes the loop condition to access c->tid with READ_ONCE.
This ensures that the value is reloaded even when the compiler would
otherwise assume it could cache the value, and also ensures that the
load will not be torn.

Signed-off-by: Mark Rutland <[email protected]>
Cc: Catalin Marinas <[email protected]>
Acked-by: Christoph Lameter <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Jesper Dangaard Brouer <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Steve Capper <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
koenkooi pushed a commit that referenced this pull request Apr 15, 2015
…he maximum open files

The soft maximum number of open files for a calling process is 1024,
which is defined as INR_OPEN_CUR in include/uapi/linux/fs.h, and the
hard maximum number of open files for a calling process is 4096, which
is defined as INR_OPEN_MAX in include/uapi/linux/fs.h.

Both INR_OPEN_CUR and INR_OPEN_MAX are used to limit the value of
RLIMIT_NOFILE in include/asm-generic/resource.h.

And the soft maximum number finally decides the limitation of the
maximum files which are allowed to be opened.

That is to say a process can use at most 1024 file descriptors for its
o pened files, or an EMFILE error will happen.

This error can be fixed by increasing the soft maximum number, under the
constraint that the soft maximum number can not exceed the hard maximum
number, or both soft and hard maximum number should be increased
simultaneously with privilege.

For perf sched replay, it uses sys_perf_event_open to create the file
descriptor for each of the tasks in order to handle information of perf
events.

That is to say each task needs a unique file descriptor. In x86_64,
there may be over 1024 or 4096 tasks correspoinding to the record in
perf.data, which causes that no enough file descriptors can be used.

As a result, EMFILE error happens and stops the replay process. To solve
this problem, we adaptively increase the soft and hard maximum number of
open files with a '-f' option.

Example:

Test environment: x86_64 with 160 cores

 $ cat /proc/sys/kernel/pid_max
 163840
 $ cat /proc/sys/fs/file-max
 6815744
 $ ulimit -Sn
 1024
 $ ulimit -Hn
 4096

Before this patch:

 $ perf sched replay
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 Error: sys_perf_event_open() syscall returned with -1 (Too many open
 files)

After this patch:

 $ perf sched replay
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 Error: sys_perf_event_open() syscall returned with -1 (Too many open
 files)
 Have a try with -f option

 $ perf sched replay -f
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 ------------------------------------------------------------
 #1  : 54.401, ravg: 54.40, cpu: 3285.21 / 3285.21
 #2  : 199.548, ravg: 68.92, cpu: 4999.65 / 3456.66
 #3  : 170.483, ravg: 79.07, cpu: 1349.94 / 3245.99
 #4  : 192.034, ravg: 90.37, cpu: 1322.88 / 3053.67
 #5  : 182.929, ravg: 99.62, cpu: 1406.51 / 2888.96
 #6  : 152.974, ravg: 104.96, cpu: 1167.54 / 2716.82
 #7  : 155.579, ravg: 110.02, cpu: 2992.53 / 2744.39
 #8  : 130.557, ravg: 112.08, cpu: 1126.43 / 2582.59
 #9  : 138.520, ravg: 114.72, cpu: 1253.22 / 2449.65
 #10 : 134.328, ravg: 116.68, cpu: 1587.95 / 2363.48

Signed-off-by: Yunlong Song <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
koenkooi pushed a commit that referenced this pull request Apr 15, 2015
Enable to use perf.data when it is not owned by current user or root.

Example:

 $ ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 5321918 Mar 25 15:14 perf.data
 $ sudo id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 $ sudo perf sched replay -f
 run measurement overhead: 98 nsecs
 sleep measurement overhead: 52909 nsecs
 the run test took 1000015 nsecs
 the sleep test took 1054253 nsecs
 File perf.data not owned by current user or root (use -f to override)

As shown above, the -f option does not work at all.

After this patch:

 $ sudo perf sched replay -f
 run measurement overhead: 221 nsecs
 sleep measurement overhead: 40514 nsecs
 the run test took 1000003 nsecs
 the sleep test took 1056098 nsecs
 nr_run_events:        10
 nr_sleep_events:      1562
 nr_wakeup_events:     5
 task      0 (                  :1:         1), nr_events: 1
 task      1 (                  :2:         2), nr_events: 1
 task      2 (                  :3:         3), nr_events: 1
 ...
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 ------------------------------------------------------------
 #1  : 50.198, ravg: 50.20, cpu: 2335.18 / 2335.18
 #2  : 219.099, ravg: 67.09, cpu: 2835.11 / 2385.17
 #3  : 238.626, ravg: 84.24, cpu: 3278.26 / 2474.48
 #4  : 200.364, ravg: 95.85, cpu: 2977.41 / 2524.77
 #5  : 176.882, ravg: 103.96, cpu: 2801.35 / 2552.43
 #6  : 191.093, ravg: 112.67, cpu: 2813.70 / 2578.56
 #7  : 189.448, ravg: 120.35, cpu: 2809.21 / 2601.62
 #8  : 200.637, ravg: 128.38, cpu: 2849.91 / 2626.45
 #9  : 248.338, ravg: 140.37, cpu: 4380.61 / 2801.87
 #10 : 511.139, ravg: 177.45, cpu: 3077.73 / 2829.45

As shown above, the -f option really works now.

Besides for replay, -f option can also work for latency and map.

Signed-off-by: Yunlong Song <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
docularxu added a commit that referenced this pull request Apr 27, 2015
Add a u32 in struct wl1271 to make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
koenkooi pushed a commit that referenced this pull request May 7, 2015
Perf top raise a warning if a kernel sample is collected but kernel map
is restricted. The warning message needs to dereference al.map->dso...

However, previous perf_event__preprocess_sample() doesn't always
guarantee al.map != NULL, for example, when kernel map is restricted.

This patch validates al.map before dereferencing, avoid the segfault.

Before this patch:

 $ cat /proc/sys/kernel/kptr_restrict
 1
 $ perf top -p  120183
 perf: Segmentation fault
 -------- backtrace --------
 /path/to/perf[0x509868]
 /lib64/libc.so.6(+0x3545f)[0x7f9a1540045f]
 /path/to/perf[0x448820]
 /path/to/perf(cmd_top+0xe3c)[0x44a5dc]
 /path/to/perf[0x4766a2]
 /path/to/perf(main+0x5f5)[0x42e545]
 /lib64/libc.so.6(__libc_start_main+0xf4)[0x7f9a153ecbd4]
 /path/to/perf[0x42e674]

And gdb call trace:

 Program received signal SIGSEGV, Segmentation fault.
 perf_event__process_sample (machine=0xa44030, sample=0x7fffffffa4c0, evsel=0xa43b00, event=0x7ffff41c3000, tool=0x7fffffffa8a0)
    at builtin-top.c:736
 736				  !RB_EMPTY_ROOT(&al.map->dso->symbols[MAP__FUNCTION]) ?
 (gdb) bt
 #0  perf_event__process_sample (machine=0xa44030, sample=0x7fffffffa4c0, evsel=0xa43b00, event=0x7ffff41c3000, tool=0x7fffffffa8a0)
     at builtin-top.c:736
 #1  perf_top__mmap_read_idx (top=top@entry=0x7fffffffa8a0, idx=idx@entry=0) at builtin-top.c:855
 #2  0x000000000044a5dd in perf_top__mmap_read (top=0x7fffffffa8a0) at builtin-top.c:872
 #3  __cmd_top (top=0x7fffffffa8a0) at builtin-top.c:997
 #4  cmd_top (argc=<optimized out>, argv=<optimized out>, prefix=<optimized out>) at builtin-top.c:1267
 #5  0x00000000004766a3 in run_builtin (p=p@entry=0x8a6ce8 <commands+264>, argc=argc@entry=3, argv=argv@entry=0x7fffffffdf70)
      at perf.c:371
 #6  0x000000000042e546 in handle_internal_command (argv=0x7fffffffdf70, argc=3) at perf.c:430
 #7  run_argv (argv=0x7fffffffdcf0, argcp=0x7fffffffdcfc) at perf.c:474
 #8  main (argc=3, argv=0x7fffffffdf70) at perf.c:589
 (gdb)

Signed-off-by: Wang Nan <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Zefan Li <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
docularxu added a commit that referenced this pull request May 17, 2015
Add a u32 in struct wl1271 to make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
docularxu added a commit that referenced this pull request May 22, 2015
Add a u32 in struct wl1271 to make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
docularxu added a commit that referenced this pull request Oct 21, 2015
In struct wl1271, make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
docularxu pushed a commit that referenced this pull request Oct 26, 2015
My colleague ran into a program stall on a x86_64 server, where
n_tty_read() was waiting for data even if there was data in the buffer
in the pty.  kernel stack for the stuck process looks like below.
 #0 [ffff88303d107b58] __schedule at ffffffff815c4b20
 #1 [ffff88303d107bd0] schedule at ffffffff815c513e
 #2 [ffff88303d107bf0] schedule_timeout at ffffffff815c7818
 #3 [ffff88303d107ca0] wait_woken at ffffffff81096bd2
 #4 [ffff88303d107ce0] n_tty_read at ffffffff8136fa23
 #5 [ffff88303d107dd0] tty_read at ffffffff81368013
 #6 [ffff88303d107e20] __vfs_read at ffffffff811a3704
 #7 [ffff88303d107ec0] vfs_read at ffffffff811a3a57
 #8 [ffff88303d107f00] sys_read at ffffffff811a4306
 #9 [ffff88303d107f50] entry_SYSCALL_64_fastpath at ffffffff815c86d7

There seems to be two problems causing this issue.

First, in drivers/tty/n_tty.c, __receive_buf() stores the data and
updates ldata->commit_head using smp_store_release() and then checks
the wait queue using waitqueue_active().  However, since there is no
memory barrier, __receive_buf() could return without calling
wake_up_interactive_poll(), and at the same time, n_tty_read() could
start to wait in wait_woken() as in the following chart.

        __receive_buf()                         n_tty_read()
------------------------------------------------------------------------
if (waitqueue_active(&tty->read_wait))
/* Memory operations issued after the
   RELEASE may be completed before the
   RELEASE operation has completed */
                                        add_wait_queue(&tty->read_wait, &wait);
                                        ...
                                        if (!input_available_p(tty, 0)) {
smp_store_release(&ldata->commit_head,
                  ldata->read_head);
                                        ...
                                        timeout = wait_woken(&wait,
                                          TASK_INTERRUPTIBLE, timeout);
------------------------------------------------------------------------

The second problem is that n_tty_read() also lacks a memory barrier
call and could also cause __receive_buf() to return without calling
wake_up_interactive_poll(), and n_tty_read() to wait in wait_woken()
as in the chart below.

        __receive_buf()                         n_tty_read()
------------------------------------------------------------------------
                                        spin_lock_irqsave(&q->lock, flags);
                                        /* from add_wait_queue() */
                                        ...
                                        if (!input_available_p(tty, 0)) {
                                        /* Memory operations issued after the
                                           RELEASE may be completed before the
                                           RELEASE operation has completed */
smp_store_release(&ldata->commit_head,
                  ldata->read_head);
if (waitqueue_active(&tty->read_wait))
                                        __add_wait_queue(q, wait);
                                        spin_unlock_irqrestore(&q->lock,flags);
                                        /* from add_wait_queue() */
                                        ...
                                        timeout = wait_woken(&wait,
                                          TASK_INTERRUPTIBLE, timeout);
------------------------------------------------------------------------

There are also other places in drivers/tty/n_tty.c which have similar
calls to waitqueue_active(), so instead of adding many memory barrier
calls, this patch simply removes the call to waitqueue_active(),
leaving just wake_up*() behind.

This fixes both problems because, even though the memory access before
or after the spinlocks in both wake_up*() and add_wait_queue() can
sneak into the critical section, it cannot go past it and the critical
section assures that they will be serialized (please see "INTER-CPU
ACQUIRING BARRIER EFFECTS" in Documentation/memory-barriers.txt for a
better explanation).  Moreover, the resulting code is much simpler.

Latency measurement using a ping-pong test over a pty doesn't show any
visible performance drop.

Signed-off-by: Kosuke Tatsukawa <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
docularxu added a commit that referenced this pull request Oct 29, 2015
Add a u32 in struct wl1271 to make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
docularxu added a commit that referenced this pull request Nov 19, 2015
In struct wl1271, make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
docularxu added a commit that referenced this pull request Dec 3, 2015
In struct wl1271, make fields reg_ch_conf_last and
reg_ch_conf_pending 64bit aligned.

Without this, on 64bit ARM, wlcore_set_pending_regdomain_ch() will fail at
the point it calls set_bit(ch_bit_idx, (long*)wl->reg_ch_conf_pending);
Here is the error message while doing iw wlan0 scan or connect:

[  760.644782] wlcore: WL1271_ACX_INTR_DATA
[  760.648734] Unhandled fault: alignment fault (0x96000021) at 0xffffffc01bdc1b54
[  760.656048] Internal error: : 96000021 [#1] PREEMPT SMP
[  760.661267] Modules linked in: arc4 wl18xx wlcore mac80211 cfg80211 wlcore_sdio ti_conf_wl18xx btwilink st_drv bluetooth rfkill
[  760.672824] CPU: 0 PID: 1514 Comm: irq/198-wl18xx Tainted: G        W    3.10.52-wl-00204-gf704232-dirty #8
[  760.682558] task: ffffffc01d956040 ti: ffffffc01bea4000 task.ti: ffffffc01bea4000
[  760.690043] PC is at set_bit+0x14/0x30
[  760.693806] LR is at wlcore_set_pending_regdomain_ch+0x38/0x44 [wlcore]

Signed-off-by: Guodong Xu <[email protected]>
johnstultz-work pushed a commit that referenced this pull request Jan 5, 2016
commit ecf5fc6 upstream.

Nikolay has reported a hang when a memcg reclaim got stuck with the
following backtrace:

PID: 18308  TASK: ffff883d7c9b0a30  CPU: 1   COMMAND: "rsync"
  #0 __schedule at ffffffff815ab152
  #1 schedule at ffffffff815ab76e
  #2 schedule_timeout at ffffffff815ae5e5
  #3 io_schedule_timeout at ffffffff815aad6a
  #4 bit_wait_io at ffffffff815abfc6
  #5 __wait_on_bit at ffffffff815abda5
  #6 wait_on_page_bit at ffffffff8111fd4f
  #7 shrink_page_list at ffffffff81135445
  #8 shrink_inactive_list at ffffffff81135845
  #9 shrink_lruvec at ffffffff81135ead
 #10 shrink_zone at ffffffff811360c3
 #11 shrink_zones at ffffffff81136eff
 #12 do_try_to_free_pages at ffffffff8113712f
 #13 try_to_free_mem_cgroup_pages at ffffffff811372be
 #14 try_charge at ffffffff81189423
 #15 mem_cgroup_try_charge at ffffffff8118c6f5
 #16 __add_to_page_cache_locked at ffffffff8112137d
 #17 add_to_page_cache_lru at ffffffff81121618
 #18 pagecache_get_page at ffffffff8112170b
 #19 grow_dev_page at ffffffff811c8297
 #20 __getblk_slow at ffffffff811c91d6
 #21 __getblk_gfp at ffffffff811c92c1
 #22 ext4_ext_grow_indepth at ffffffff8124565c
 #23 ext4_ext_create_new_leaf at ffffffff81246ca8
 #24 ext4_ext_insert_extent at ffffffff81246f09
 #25 ext4_ext_map_blocks at ffffffff8124a848
 #26 ext4_map_blocks at ffffffff8121a5b7
 #27 mpage_map_one_extent at ffffffff8121b1fa
 #28 mpage_map_and_submit_extent at ffffffff8121f07b
 #29 ext4_writepages at ffffffff8121f6d5
 #30 do_writepages at ffffffff8112c490
 #31 __filemap_fdatawrite_range at ffffffff81120199
 #32 filemap_flush at ffffffff8112041c
 #33 ext4_alloc_da_blocks at ffffffff81219da1
 #34 ext4_rename at ffffffff81229b91
 #35 ext4_rename2 at ffffffff81229e32
 #36 vfs_rename at ffffffff811a08a5
 #37 SYSC_renameat2 at ffffffff811a3ffc
 #38 sys_renameat2 at ffffffff811a408e
 #39 sys_rename at ffffffff8119e51e
 #40 system_call_fastpath at ffffffff815afa89

Dave Chinner has properly pointed out that this is a deadlock in the
reclaim code because ext4 doesn't submit pages which are marked by
PG_writeback right away.

The heuristic was introduced by commit e62e384 ("memcg: prevent OOM
with too many dirty pages") and it was applied only when may_enter_fs
was specified.  The code has been changed by c3b94f4 ("memcg:
further prevent OOM with too many dirty pages") which has removed the
__GFP_FS restriction with a reasoning that we do not get into the fs
code.  But this is not sufficient apparently because the fs doesn't
necessarily submit pages marked PG_writeback for IO right away.

ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily
submit the bio.  Instead it tries to map more pages into the bio and
mpage_map_one_extent might trigger memcg charge which might end up
waiting on a page which is marked PG_writeback but hasn't been submitted
yet so we would end up waiting for something that never finishes.

Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2)
before we go to wait on the writeback.  The page fault path, which is
the only path that triggers memcg oom killer since 3.12, shouldn't
require GFP_NOFS and so we shouldn't reintroduce the premature OOM
killer issue which was originally addressed by the heuristic.

As per David Chinner the xfs is doing similar thing since 2.6.15 already
so ext4 is not the only affected filesystem.  Moreover he notes:

: For example: IO completion might require unwritten extent conversion
: which executes filesystem transactions and GFP_NOFS allocations. The
: writeback flag on the pages can not be cleared until unwritten
: extent conversion completes. Hence memory reclaim cannot wait on
: page writeback to complete in GFP_NOFS context because it is not
: safe to do so, memcg reclaim or otherwise.

Cc: [email protected] # 3.9+
[[email protected]: corrected the control flow]
Fixes: c3b94f4 ("memcg: further prevent OOM with too many dirty pages")
Reported-by: Nikolay Borisov <[email protected]>
Signed-off-by: Michal Hocko <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
johnstultz-work pushed a commit that referenced this pull request Jan 5, 2016
commit fc5fee8 upstream.

It turns out that a PV domU also requires the "Xen PV" APIC
driver. Otherwise, the flat driver is used and we get stuck in busy
loops that never exit, such as in this stack trace:

(gdb) target remote localhost:9999
Remote debugging using localhost:9999
__xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
56              while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
(gdb) bt
 #0  __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
 #1  __default_send_IPI_shortcut (shortcut=<optimized out>,
dest=<optimized out>, vector=<optimized out>) at
./arch/x86/include/asm/ipi.h:75
 #2  apic_send_IPI_self (vector=246) at arch/x86/kernel/apic/probe_64.c:54
 #3  0xffffffff81011336 in arch_irq_work_raise () at
arch/x86/kernel/irq_work.c:47
 #4  0xffffffff8114990c in irq_work_queue (work=0xffff88000fc0e400) at
kernel/irq_work.c:100
 #5  0xffffffff8110c29d in wake_up_klogd () at kernel/printk/printk.c:2633
 #6  0xffffffff8110ca60 in vprintk_emit (facility=0, level=<optimized
out>, dict=0x0 <irq_stack_union>, dictlen=<optimized out>,
fmt=<optimized out>, args=<optimized out>)
    at kernel/printk/printk.c:1778
 #7  0xffffffff816010c8 in printk (fmt=<optimized out>) at
kernel/printk/printk.c:1868
 #8  0xffffffffc00013ea in ?? ()
 #9  0x0000000000000000 in ?? ()

Mailing-list-thread: https://lkml.org/lkml/2015/8/4/755
Signed-off-by: Jason A. Donenfeld <[email protected]>
Signed-off-by: David Vrabel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
johnstultz-work pushed a commit that referenced this pull request Jan 5, 2016
…ther

[ Upstream commit 06f6d10 ]

When the bonding is being unloaded and the netdevice notifier is
unregistered it executes NETDEV_UNREGISTER for each device which should
remove the bond's proc entry but if the device enslaved is not of
ARPHRD_ETHER type and is in front of the bonding, it may execute
bond_release_and_destroy() first which would release the last slave and
destroy the bond device leaving the proc entry and thus we will get the
following error (with dynamic debug on for bond_netdev_event to see the
events order):
[  908.963051] eql: event: 9
[  908.963052] eql: IFF_SLAVE
[  908.963054] eql: event: 2
[  908.963056] eql: IFF_SLAVE
[  908.963058] eql: event: 6
[  908.963059] eql: IFF_SLAVE
[  908.963110] bond0: Releasing active interface eql
[  908.976168] bond0: Destroying bond bond0
[  908.976266] bond0 (unregistering): Released all slaves
[  908.984097] ------------[ cut here ]------------
[  908.984107] WARNING: CPU: 0 PID: 1787 at fs/proc/generic.c:575
remove_proc_entry+0x112/0x160()
[  908.984110] remove_proc_entry: removing non-empty directory
'net/bonding', leaking at least 'bond0'
[  908.984111] Modules linked in: bonding(-) eql(O) 9p nfsd auth_rpcgss
oid_registry nfs_acl nfs lockd grace fscache sunrpc crct10dif_pclmul
crc32_pclmul crc32c_intel ghash_clmulni_intel ppdev qxl drm_kms_helper
snd_hda_codec_generic aesni_intel ttm aes_x86_64 glue_helper pcspkr lrw
gf128mul ablk_helper cryptd snd_hda_intel virtio_console snd_hda_codec
psmouse serio_raw snd_hwdep snd_hda_core 9pnet_virtio 9pnet evdev joydev
drm virtio_balloon snd_pcm snd_timer snd soundcore i2c_piix4 i2c_core
pvpanic acpi_cpufreq parport_pc parport processor thermal_sys button
autofs4 ext4 crc16 mbcache jbd2 hid_generic usbhid hid sg sr_mod cdrom
ata_generic virtio_blk virtio_net floppy ata_piix e1000 libata ehci_pci
virtio_pci scsi_mod uhci_hcd ehci_hcd virtio_ring virtio usbcore
usb_common [last unloaded: bonding]

[  908.984168] CPU: 0 PID: 1787 Comm: rmmod Tainted: G        W  O
4.2.0-rc2+ #8
[  908.984170] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  908.984172]  0000000000000000 ffffffff81732d41 ffffffff81525b34
ffff8800358dfda8
[  908.984175]  ffffffff8106c521 ffff88003595af78 ffff88003595af40
ffff88003e3a4280
[  908.984178]  ffffffffa058d040 0000000000000000 ffffffff8106c59a
ffffffff8172ebd0
[  908.984181] Call Trace:
[  908.984188]  [<ffffffff81525b34>] ? dump_stack+0x40/0x50
[  908.984193]  [<ffffffff8106c521>] ? warn_slowpath_common+0x81/0xb0
[  908.984196]  [<ffffffff8106c59a>] ? warn_slowpath_fmt+0x4a/0x50
[  908.984199]  [<ffffffff81218352>] ? remove_proc_entry+0x112/0x160
[  908.984205]  [<ffffffffa05850e6>] ? bond_destroy_proc_dir+0x26/0x30
[bonding]
[  908.984208]  [<ffffffffa057540e>] ? bond_net_exit+0x8e/0xa0 [bonding]
[  908.984217]  [<ffffffff8142f407>] ? ops_exit_list.isra.4+0x37/0x70
[  908.984225]  [<ffffffff8142f52d>] ?
unregister_pernet_operations+0x8d/0xd0
[  908.984228]  [<ffffffff8142f58d>] ?
unregister_pernet_subsys+0x1d/0x30
[  908.984232]  [<ffffffffa0585269>] ? bonding_exit+0x23/0xdba [bonding]
[  908.984236]  [<ffffffff810e28ba>] ? SyS_delete_module+0x18a/0x250
[  908.984241]  [<ffffffff81086f99>] ? task_work_run+0x89/0xc0
[  908.984244]  [<ffffffff8152b732>] ?
entry_SYSCALL_64_fastpath+0x16/0x75
[  908.984247] ---[ end trace 7c006ed4abbef24b ]---

Thus remove the proc entry manually if bond_release_and_destroy() is
used. Because of the checks in bond_remove_proc_entry() it's not a
problem for a bond device to change namespaces (the bug fixed by the
Fixes commit) but since commit
f939981 ("bonding: Don't allow bond devices to change network
namespaces.") that can't happen anyway.

Reported-by: Carol Soto <[email protected]>
Signed-off-by: Nikolay Aleksandrov <[email protected]>
Fixes: a64d49c ("bonding: Manage /proc/net/bonding/ entries from
                      the netdev events")
Tested-by: Carol L Soto <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
johnstultz-work pushed a commit that referenced this pull request Jan 5, 2016
commit e81107d upstream.

My colleague ran into a program stall on a x86_64 server, where
n_tty_read() was waiting for data even if there was data in the buffer
in the pty.  kernel stack for the stuck process looks like below.
 #0 [ffff88303d107b58] __schedule at ffffffff815c4b20
 #1 [ffff88303d107bd0] schedule at ffffffff815c513e
 #2 [ffff88303d107bf0] schedule_timeout at ffffffff815c7818
 #3 [ffff88303d107ca0] wait_woken at ffffffff81096bd2
 #4 [ffff88303d107ce0] n_tty_read at ffffffff8136fa23
 #5 [ffff88303d107dd0] tty_read at ffffffff81368013
 #6 [ffff88303d107e20] __vfs_read at ffffffff811a3704
 #7 [ffff88303d107ec0] vfs_read at ffffffff811a3a57
 #8 [ffff88303d107f00] sys_read at ffffffff811a4306
 #9 [ffff88303d107f50] entry_SYSCALL_64_fastpath at ffffffff815c86d7

There seems to be two problems causing this issue.

First, in drivers/tty/n_tty.c, __receive_buf() stores the data and
updates ldata->commit_head using smp_store_release() and then checks
the wait queue using waitqueue_active().  However, since there is no
memory barrier, __receive_buf() could return without calling
wake_up_interactive_poll(), and at the same time, n_tty_read() could
start to wait in wait_woken() as in the following chart.

        __receive_buf()                         n_tty_read()
------------------------------------------------------------------------
if (waitqueue_active(&tty->read_wait))
/* Memory operations issued after the
   RELEASE may be completed before the
   RELEASE operation has completed */
                                        add_wait_queue(&tty->read_wait, &wait);
                                        ...
                                        if (!input_available_p(tty, 0)) {
smp_store_release(&ldata->commit_head,
                  ldata->read_head);
                                        ...
                                        timeout = wait_woken(&wait,
                                          TASK_INTERRUPTIBLE, timeout);
------------------------------------------------------------------------

The second problem is that n_tty_read() also lacks a memory barrier
call and could also cause __receive_buf() to return without calling
wake_up_interactive_poll(), and n_tty_read() to wait in wait_woken()
as in the chart below.

        __receive_buf()                         n_tty_read()
------------------------------------------------------------------------
                                        spin_lock_irqsave(&q->lock, flags);
                                        /* from add_wait_queue() */
                                        ...
                                        if (!input_available_p(tty, 0)) {
                                        /* Memory operations issued after the
                                           RELEASE may be completed before the
                                           RELEASE operation has completed */
smp_store_release(&ldata->commit_head,
                  ldata->read_head);
if (waitqueue_active(&tty->read_wait))
                                        __add_wait_queue(q, wait);
                                        spin_unlock_irqrestore(&q->lock,flags);
                                        /* from add_wait_queue() */
                                        ...
                                        timeout = wait_woken(&wait,
                                          TASK_INTERRUPTIBLE, timeout);
------------------------------------------------------------------------

There are also other places in drivers/tty/n_tty.c which have similar
calls to waitqueue_active(), so instead of adding many memory barrier
calls, this patch simply removes the call to waitqueue_active(),
leaving just wake_up*() behind.

This fixes both problems because, even though the memory access before
or after the spinlocks in both wake_up*() and add_wait_queue() can
sneak into the critical section, it cannot go past it and the critical
section assures that they will be serialized (please see "INTER-CPU
ACQUIRING BARRIER EFFECTS" in Documentation/memory-barriers.txt for a
better explanation).  Moreover, the resulting code is much simpler.

Latency measurement using a ping-pong test over a pty doesn't show any
visible performance drop.

Signed-off-by: Kosuke Tatsukawa <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
docularxu pushed a commit that referenced this pull request Jan 11, 2016
When a43eec3 ("bpf: introduce bpf_perf_event_output() helper") added
PERF_COUNT_SW_BPF_OUTPUT we ended up with a new entry in the event_symbols_sw
array that wasn't initialized, thus set to NULL, fix print_symbol_events()
to check for that case so that we don't crash if this happens again.

  (gdb) bt
  #0  __match_glob (ignore_space=false, pat=<optimized out>, str=<optimized out>) at util/string.c:198
  #1  strglobmatch (str=<optimized out>, pat=pat@entry=0x7fffffffe61d "stall") at util/string.c:252
  #2  0x00000000004993a5 in print_symbol_events (type=1, syms=0x872880 <event_symbols_sw+160>, max=11, name_only=false, event_glob=0x7fffffffe61d "stall")
      at util/parse-events.c:1615
  #3  print_events (event_glob=event_glob@entry=0x7fffffffe61d "stall", name_only=false) at util/parse-events.c:1675
  #4  0x000000000042c79e in cmd_list (argc=1, argv=0x7fffffffe390, prefix=<optimized out>) at builtin-list.c:68
  #5  0x00000000004788a5 in run_builtin (p=p@entry=0x871758 <commands+120>, argc=argc@entry=2, argv=argv@entry=0x7fffffffe390) at perf.c:370
  #6  0x0000000000420ab0 in handle_internal_command (argv=0x7fffffffe390, argc=2) at perf.c:429
  #7  run_argv (argv=0x7fffffffe110, argcp=0x7fffffffe11c) at perf.c:473
  #8  main (argc=2, argv=0x7fffffffe390) at perf.c:588
  (gdb) p event_symbols_sw[PERF_COUNT_SW_BPF_OUTPUT]
  $4 = {symbol = 0x0, alias = 0x0}
  (gdb)

A patch to robustify perf to not segfault when the next counter gets added in
the kernel will follow this one.

Reported-by: Ingo Molnar <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
idlethread pushed a commit that referenced this pull request Apr 21, 2016
commit ec183d2 upstream.

Fixes segmentation fault using, for instance:

  (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib64/libthread_db.so.1".

 Program received signal SIGSEGV, Segmentation fault.
  0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  (gdb) bt
  #0  0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  #1  0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:433
  #2  0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:498
  #3  0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:936
  #4  0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391
  #5  0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361
  #6  0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401
  #7  0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253
  #8  0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364
  #9  0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664
  #10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539
  #11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264
  #12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390
  #13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451
  #14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495
  #15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618
(gdb)

Intel PT attempts to find the sched:sched_switch tracepoint but that seg
faults if tracefs is not readable, because the error reporting structure
is null, as errors are not reported when automatically adding
tracepoints.  Fix by checking before using.

Committer note:

This doesn't take place in a kernel that supports
perf_event_attr.context_switch, that is the default way that will be
used for tracking context switches, only in older kernels, like 4.2, in
a machine with Intel PT (e.g. Broadwell) for non-priviledged users.

Further info from a similar patch by Wang:

The error is in tracepoint_error: it assumes the 'e' parameter is valid.

However, there are many situation a parse_event() can be called without
parse_events_error. See result of

  $ grep 'parse_events(.*NULL)' ./tools/perf/ -r'

Signed-off-by: Adrian Hunter <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Tong Zhang <[email protected]>
Cc: Wang Nan <[email protected]>
Fixes: 1965817 ("perf tools: Enhance parsing events tracepoint error output")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nyadla-sys pushed a commit to nyadla-sys/linux that referenced this pull request Apr 24, 2017
[ Upstream commit 45caeaa ]

As Eric Dumazet pointed out this also needs to be fixed in IPv6.
v2: Contains the IPv6 tcp/Ipv6 dccp patches as well.

We have seen a few incidents lately where a dst_enty has been freed
with a dangling TCP socket reference (sk->sk_dst_cache) pointing to that
dst_entry. If the conditions/timings are right a crash then ensues when the
freed dst_entry is referenced later on. A Common crashing back trace is:

 96boards#8 [] page_fault at ffffffff8163e648
    [exception RIP: __tcp_ack_snd_check+74]
.
.
 96boards#9 [] tcp_rcv_established at ffffffff81580b64
96boards#10 [] tcp_v4_do_rcv at ffffffff8158b54a
96boards#11 [] tcp_v4_rcv at ffffffff8158cd02
96boards#12 [] ip_local_deliver_finish at ffffffff815668f4
96boards#13 [] ip_local_deliver at ffffffff81566bd9
96boards#14 [] ip_rcv_finish at ffffffff8156656d
96boards#15 [] ip_rcv at ffffffff81566f06
#16 [] __netif_receive_skb_core at ffffffff8152b3a2
#17 [] __netif_receive_skb at ffffffff8152b608
#18 [] netif_receive_skb at ffffffff8152b690
#19 [] vmxnet3_rq_rx_complete at ffffffffa015eeaf [vmxnet3]
#20 [] vmxnet3_poll_rx_only at ffffffffa015f32a [vmxnet3]
96boards#21 [] net_rx_action at ffffffff8152bac2
96boards#22 [] __do_softirq at ffffffff81084b4f
96boards#23 [] call_softirq at ffffffff8164845c
96boards#24 [] do_softirq at ffffffff81016fc5
96boards#25 [] irq_exit at ffffffff81084ee5
96boards#26 [] do_IRQ at ffffffff81648ff8

Of course it may happen with other NIC drivers as well.

It's found the freed dst_entry here:

 224 static bool tcp_in_quickack_mode(struct sock *sk)↩
 225 {↩
 226 ▹       const struct inet_connection_sock *icsk = inet_csk(sk);↩
 227 ▹       const struct dst_entry *dst = __sk_dst_get(sk);↩
 228 ↩
 229 ▹       return (dst && dst_metric(dst, RTAX_QUICKACK)) ||↩
 230 ▹       ▹       (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);↩
 231 }↩

But there are other backtraces attributed to the same freed dst_entry in
netfilter code as well.

All the vmcores showed 2 significant clues:

- Remote hosts behind the default gateway had always been redirected to a
different gateway. A rtable/dst_entry will be added for that host. Making
more dst_entrys with lower reference counts. Making this more probable.

- All vmcores showed a postitive LockDroppedIcmps value, e.g:

LockDroppedIcmps                  267

A closer look at the tcp_v4_err() handler revealed that do_redirect() will run
regardless of whether user space has the socket locked. This can result in a
race condition where the same dst_entry cached in sk->sk_dst_entry can be
decremented twice for the same socket via:

do_redirect()->__sk_dst_check()-> dst_release().

Which leads to the dst_entry being prematurely freed with another socket
pointing to it via sk->sk_dst_cache and a subsequent crash.

To fix this skip do_redirect() if usespace has the socket locked. Instead let
the redirect take place later when user space does not have the socket
locked.

The dccp/IPv6 code is very similar in this respect, so fixing it there too.

As Eric Garver pointed out the following commit now invalidates routes. Which
can set the dst->obsolete flag so that ipv4_dst_check() returns null and
triggers the dst_release().

Fixes: ceb3320 ("ipv4: Kill routes during PMTU/redirect updates.")
Cc: Eric Garver <[email protected]>
Cc: Hannes Sowa <[email protected]>
Signed-off-by: Jon Maxwell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nyadla-sys pushed a commit to nyadla-sys/linux that referenced this pull request Jun 13, 2017
commit a575813 upstream.

Reported by syzkaller:

   BUG: unable to handle kernel paging request at ffffffffc07f6a2e
   IP: report_bug+0x94/0x120
   PGD 348e12067
   P4D 348e12067
   PUD 348e14067
   PMD 3cbd84067
   PTE 80000003f7e87161

   Oops: 0003 [#1] SMP
   CPU: 2 PID: 7091 Comm: kvm_load_guest_ Tainted: G           OE   4.11.0+ 96boards#8
   task: ffff92fdfb525400 task.stack: ffffbda6c3d04000
   RIP: 0010:report_bug+0x94/0x120
   RSP: 0018:ffffbda6c3d07b20 EFLAGS: 00010202
    do_trap+0x156/0x170
    do_error_trap+0xa3/0x170
    ? kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? mark_held_locks+0x79/0xa0
    ? retint_kernel+0x10/0x10
    ? trace_hardirqs_off_thunk+0x1a/0x1c
    do_invalid_op+0x20/0x30
    invalid_op+0x1e/0x30
   RIP: 0010:kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? kvm_load_guest_fpu.part.175+0x1c/0x170 [kvm]
    kvm_arch_vcpu_ioctl_run+0xed6/0x1b70 [kvm]
    kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? sched_clock+0x13/0x20
    ? __do_page_fault+0x2a0/0x550
    do_vfs_ioctl+0xa4/0x700
    ? up_read+0x1f/0x40
    ? __do_page_fault+0x2a0/0x550
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x23/0xc2

SDM mentioned that "The MXCSR has several reserved bits, and attempting to write
a 1 to any of these bits will cause a general-protection exception(#GP) to be
generated". The syzkaller forks' testcase overrides xsave area w/ random values
and steps on the reserved bits of MXCSR register. The damaged MXCSR register
values of guest will be restored to SSEx MXCSR register before vmentry. This
patch fixes it by catching userspace override MXCSR register reserved bits w/
random values and bails out immediately.

Reported-by: Andrey Konovalov <[email protected]>
Reviewed-by: Paolo Bonzini <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Radim Krčmář <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
nyadla-sys pushed a commit to nyadla-sys/linux that referenced this pull request Jun 13, 2017
commit a575813 upstream.

Reported by syzkaller:

   BUG: unable to handle kernel paging request at ffffffffc07f6a2e
   IP: report_bug+0x94/0x120
   PGD 348e12067
   P4D 348e12067
   PUD 348e14067
   PMD 3cbd84067
   PTE 80000003f7e87161

   Oops: 0003 [#1] SMP
   CPU: 2 PID: 7091 Comm: kvm_load_guest_ Tainted: G           OE   4.11.0+ 96boards#8
   task: ffff92fdfb525400 task.stack: ffffbda6c3d04000
   RIP: 0010:report_bug+0x94/0x120
   RSP: 0018:ffffbda6c3d07b20 EFLAGS: 00010202
    do_trap+0x156/0x170
    do_error_trap+0xa3/0x170
    ? kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? mark_held_locks+0x79/0xa0
    ? retint_kernel+0x10/0x10
    ? trace_hardirqs_off_thunk+0x1a/0x1c
    do_invalid_op+0x20/0x30
    invalid_op+0x1e/0x30
   RIP: 0010:kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? kvm_load_guest_fpu.part.175+0x1c/0x170 [kvm]
    kvm_arch_vcpu_ioctl_run+0xed6/0x1b70 [kvm]
    kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? sched_clock+0x13/0x20
    ? __do_page_fault+0x2a0/0x550
    do_vfs_ioctl+0xa4/0x700
    ? up_read+0x1f/0x40
    ? __do_page_fault+0x2a0/0x550
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x23/0xc2

SDM mentioned that "The MXCSR has several reserved bits, and attempting to write
a 1 to any of these bits will cause a general-protection exception(#GP) to be
generated". The syzkaller forks' testcase overrides xsave area w/ random values
and steps on the reserved bits of MXCSR register. The damaged MXCSR register
values of guest will be restored to SSEx MXCSR register before vmentry. This
patch fixes it by catching userspace override MXCSR register reserved bits w/
random values and bails out immediately.

Reported-by: Andrey Konovalov <[email protected]>
Reviewed-by: Paolo Bonzini <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Radim Krčmář <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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3 participants