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gpu/drm: hisilicon: Use the old stable 720P timing #22

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xin3liang
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This is the old 720p timing. It's tested as stable before.
Signed-off-by: Xinliang Liu [email protected]

@koenkooi
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Does this match CEA 681-E Format 4?

@ldts
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ldts commented Mar 13, 2015

please could you also rework the commit name and the commit log?

@ldts
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ldts commented Mar 14, 2015

hi xin3liang, what does this fix ? why should we merge this?

@ldts
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ldts commented Mar 16, 2015

please resend with further information. cheers.

@ldts ldts closed this Mar 16, 2015
@xin3liang
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Sorry ldts and koenkooi, maybe I reply all the above dounts to wrong mail list before, thus you can't see my replies. So i want to reply again here and describe more clear for this commit.
This commit intend to revert the 720p timing setting on pull request 12: "gpu/drm: hisilicon: Correct 720P's pixel clock to fix 720p didn't work at some monitors"
Fathi Boudra and me found that the 720p timing change in pull request 12 is not stable. sometimes it can display sometimes not. So i push this pull request 22 to revert the timing change.
BTW, To koenkooi, i have no idea about the CEA 681-E Format 4 , could you explain a bit more to me? Thanks.

@xin3liang
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I have resent a pull requst 27 for this change.

koenkooi pushed a commit that referenced this pull request Apr 4, 2015
If register_shrinker() failed, nfsd will cause a NULL pointer access as,

[ 9250.875465] nfsd: last server has exited, flushing export cache
[ 9251.427270] BUG: unable to handle kernel NULL pointer dereference at           (null)
[ 9251.427393] IP: [<ffffffff8136fc29>] __list_del_entry+0x29/0xd0
[ 9251.427579] PGD 13e4d067 PUD 13e4c067 PMD 0
[ 9251.427633] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 9251.427706] Modules linked in: ip6t_rpfilter ip6t_REJECT bnep bluetooth xt_conntrack cfg80211 rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw btrfs xfs microcode ppdev serio_raw pcspkr xor libcrc32c raid6_pq e1000 parport_pc parport i2c_piix4 i2c_core nfsd(OE-) auth_rpcgss nfs_acl lockd sunrpc(E) ata_generic pata_acpi
[ 9251.428240] CPU: 0 PID: 1557 Comm: rmmod Tainted: G           OE 3.16.0-rc2+ #22
[ 9251.428366] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
[ 9251.428496] task: ffff880000849540 ti: ffff8800136f4000 task.ti: ffff8800136f4000
[ 9251.428593] RIP: 0010:[<ffffffff8136fc29>]  [<ffffffff8136fc29>] __list_del_entry+0x29/0xd0
[ 9251.428696] RSP: 0018:ffff8800136f7ea0  EFLAGS: 00010207
[ 9251.428751] RAX: 0000000000000000 RBX: ffffffffa0116d48 RCX: dead000000200200
[ 9251.428814] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffa0116d48
[ 9251.428876] RBP: ffff8800136f7ea0 R08: ffff8800136f4000 R09: 0000000000000001
[ 9251.428939] R10: 8080808080808080 R11: 0000000000000000 R12: ffffffffa011a5a0
[ 9251.429002] R13: 0000000000000800 R14: 0000000000000000 R15: 00000000018ac090
[ 9251.429064] FS:  00007fb9acef0740(0000) GS:ffff88003fa00000(0000) knlGS:0000000000000000
[ 9251.429164] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9251.429221] CR2: 0000000000000000 CR3: 0000000031a17000 CR4: 00000000001407f0
[ 9251.429306] Stack:
[ 9251.429410]  ffff8800136f7eb8 ffffffff8136fcdd ffffffffa0116d20 ffff8800136f7ed0
[ 9251.429511]  ffffffff8118a0f2 0000000000000000 ffff8800136f7ee0 ffffffffa00eb765
[ 9251.429610]  ffff8800136f7ef0 ffffffffa010e93c ffff8800136f7f78 ffffffff81104ac2
[ 9251.429709] Call Trace:
[ 9251.429755]  [<ffffffff8136fcdd>] list_del+0xd/0x30
[ 9251.429896]  [<ffffffff8118a0f2>] unregister_shrinker+0x22/0x40
[ 9251.430037]  [<ffffffffa00eb765>] nfsd_reply_cache_shutdown+0x15/0x90 [nfsd]
[ 9251.430106]  [<ffffffffa010e93c>] exit_nfsd+0x9/0x6cd [nfsd]
[ 9251.430192]  [<ffffffff81104ac2>] SyS_delete_module+0x162/0x200
[ 9251.430280]  [<ffffffff81013b69>] ? do_notify_resume+0x59/0x90
[ 9251.430395]  [<ffffffff816f2369>] system_call_fastpath+0x16/0x1b
[ 9251.430457] Code: 00 00 55 48 8b 17 48 b9 00 01 10 00 00 00 ad de 48 8b 47 08 48 89 e5 48 39 ca 74 29 48 b9 00 02 20 00 00 00 ad de 48 39 c8 74 7a <4c> 8b 00 4c 39 c7 75 53 4c 8b 42 08 4c 39 c7 75 2b 48 89 42 08
[ 9251.430691] RIP  [<ffffffff8136fc29>] __list_del_entry+0x29/0xd0
[ 9251.430755]  RSP <ffff8800136f7ea0>
[ 9251.430805] CR2: 0000000000000000
[ 9251.431033] ---[ end trace 080f3050d082b4ea ]---

Signed-off-by: Kinglong Mee <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>
docularxu pushed a commit that referenced this pull request Oct 26, 2015
it was broken by 35d5d20
"mtd: mxc_nand: cleanup copy_spare function"

else we get the following error :
[   22.709507] ubi0: attaching mtd3
[   23.613470] ubi0: scanning is finished
[   23.617278] ubi0: empty MTD device detected
[   23.623219] Unhandled fault: imprecise external abort (0x1c06) at 0x9e62f0ec
[   23.630291] pgd = 9df80000
[   23.633005] [9e62f0ec] *pgd=8e60041e(bad)
[   23.637064] Internal error: : 1c06 [#1] SMP ARM
[   23.641605] Modules linked in:
[   23.644687] CPU: 0 PID: 99 Comm: ubiattach Not tainted 4.2.0-dirty #22
[   23.651222] Hardware name: Freescale i.MX53 (Device Tree Support)
[   23.657322] task: 9e687300 ti: 9dcfc000 task.ti: 9dcfc000
[   23.662744] PC is at memcpy16_toio+0x4c/0x74
[   23.667026] LR is at mxc_nand_command+0x484/0x640
[   23.671739] pc : [<803f9c08>]    lr : [<803faeb0>]    psr: 60000013
[   23.671739] sp : 9dcfdb10  ip : 9e62f0ea  fp : 9dcfdb1c
[   23.683222] r10: a09c1000  r9 : 0000001a  r8 : ffffffff
[   23.688453] r7 : ffffffff  r6 : 9e674810  r5 : 9e674810  r4 : 000000b6
[   23.694985] r3 : a09c16a4  r2 : a09c16a4  r1 : a09c16a4  r0 : 0000ffff
[   23.701521] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   23.708662] Control: 10c5387d  Table: 8df80019  DAC: 00000015
[   23.714413] Process ubiattach (pid: 99, stack limit = 0x9dcfc210)
[   23.720514] Stack: (0x9dcfdb10 to 0x9dcfe000)
[   23.724881] db00:                                     9dcfdb6c 9dcfdb20 803faeb0 803f9bc8
[   23.733069] db20: 803f227c 803f9b74 ffffffff 9e674810 9e674810 9e674810 00000040 9e62f010
[   23.741255] db40: 803faa2c 9e674b40 9e674810 803faa2c 00000400 803faa2c 00000000 9df42800
[   23.749441] db60: 9dcfdb9c 9dcfdb70 803f2024 803faa38 9e4201cc 00000000 803f0a78 9e674b40
[   23.757627] db80: 803f1f80 9e674810 00000400 00000400 9dcfdc14 9dcfdba0 803f3bd8 803f1f8c
[   23.765814] dba0: 9e4201cc 00000000 00000580 00000000 00000000 800718c0 0000007f 00001000
[   23.774000] dbc0: 9df42800 000000e0 00000000 00000000 9e4201cc 00000000 00000000 00000000
[   23.782186] dbe0: 00000580 00000580 00000000 9e674810 9dcfdc20 9dcfdce8 9df42800 00580000
[   23.790372] dc00: 00000000 00000400 9dcfdc6c 9dcfdc18 803f3f94 803f39a4 9dcfdc20 00000000
[   23.798558] dc20: 00000000 00000400 00000000 00000000 00000000 00000000 9df42800 00000000
[   23.806744] dc40: 9dcfdd0c 00580000 00000000 00000400 00000000 9df42800 9dee1000 9d802000
[   23.814930] dc60: 9dcfdc94 9dcfdc70 803eb63c 803f3f38 00000400 9dcfdce8 9df42800 dead4ead
[   23.823116] dc80: 803eb5f4 00000000 9dcfdcc4 9dcfdc98 803e82ac 803eb600 00000400 9dcfdce8
[   23.831301] dca0: 9df42800 00000400 9dee0000 00000000 00000400 00000000 9dcfdd1c 9dcfdcc8
[   23.839488] dcc0: 80406048 803e8230 00000400 9dcfdce8 9df42800 9dcfdc78 00000008 00000000
[   23.847673] dce0: 00000000 00000000 00000000 00000004 00000000 9df42800 9dee0000 00000000
[   23.855859] dd00: 9d802030 00000000 9dc8b214 9d802000 9dcfdd44 9dcfdd20 804066cc 80405f50
[   23.864047] dd20: 00000400 9dc8b200 9d802030 9df42800 9dee0000 9dc8b200 9dcfdd84 9dcfdd48
[   23.872233] dd40: 8040a544 804065ac 9e401c80 000080d0 9dcfdd84 00000001 800fc828 9df42400
[   23.880418] dd60: 00000000 00000080 9dc8b200 9dc8b200 9dc8b200 9dee0000 9dcfdddc 9dcfdd8
[   23.888605] dd80: 803fb560 8040a440 9dcfddc4 9dcfdd98 800f1428 9dee1000 a0acf000 00000000
[   23.896792] dda0: 00000000 ffffffff 00000006 00000000 9dee0000 9dee0000 00005600 00000080
[   23.904979] ddc0: 9dc8b200 a0acf000 9dc8b200 8112514c 9dcfde24 9dcfdde0 803fc08c 803fb4f0
[   23.913165] dde0: 9e401c80 00000013 9dcfde04 9dcfddf8 8006bbf8 8006ba00 9dcfde24 00000000
[   23.921351] de00: 9dee0000 00000065 9dee0000 00000001 9dc8b200 8112514c 9dcfde84 9dcfde28
[   23.929538] de20: 8040afa0 803fb948 ffffffff 00000000 9dc8b214 9dcfde40 800f1428 800f11dc
[   23.937724] de40: 9dc8b21c 9dc8b20c 9dc8b204 9dee1000 9dc8b214 8069bb60 fffff000 fffff000
[   23.945911] de60: 9e7b5400 00000000 9dee0000 9dee1000 00001000 9e7b5400 9dcfdecc 9dcfde88
[   23.954097] de80: 803ff1bc 8040a630 9dcfdea4 9dcfde98 00000800 00000800 9dcfdecc 9dcfdea8
[   23.962284] dea0: 803e8f6c 00000000 7e87ab70 9e7b5400 80113e30 00000003 9dcfc000 00000000
[   23.970470] dec0: 9dcfdf04 9dcfded0 804008cc 803feb98 ffffffff 00000003 00000000 00000000
[   23.978656] dee0: 00000000 00000000 9e7cb000 9dc193e0 7e87ab70 9dd92140 9dcfdf7c 9dcfdf08
[   23.986842] df00: 80113b5c 8040080c 800fbed8 8006bbf0 9e7cb000 00000003 9e7cb000 9dd92140
[   23.995029] df20: 9dc193e0 9dd92148 9dcfdf4c 9dcfdf38 8011022c 800fbe78 8000f9cc 9e687300
[   24.003216] df40: 9dcfdf6c 9dcfdf50 8011f798 8007ffe8 7e87ab70 9dd92140 00000003 9dd92140
[   24.011402] df60: 40186f40 7e87ab70 9dcfc000 00000000 9dcfdfa4 9dcfdf80 80113e30 8011373c
[   24.019588] df80: 7e87ab70 7e87ab70 7e87aea9 00000036 8000fb8 9dcfc000 00000000 9dcfdfa8
[   24.027775] dfa0: 8000f9a0 80113e00 7e87ab70 7e87ab70 00000003 40186f40 7e87ab70 00000000
[   24.035962] dfc0: 7e87ab70 7e87ab70 7e87aea9 00000036 00000000 00000000 76fd1f70 00000000
[   24.044148] dfe0: 76f80f8c 7e87ab28 00009810 76f80fc4 60000010 00000003 00000000 00000000
[   24.052328] Backtrace:
[   24.054806] [<803f9bbc>] (memcpy16_toio) from [<803faeb0>] (mxc_nand_command+0x484/0x640)
[   24.062996] [<803faa2c>] (mxc_nand_command) from [<803f2024>] (nand_write_page+0xa4/0x154)
[   24.071264]  r10:9df42800 r9:00000000 r8:803faa2c r7:00000400 r6:803faa2c r5:9e674810
[   24.079180]  r4:9e674b40
[   24.081738] [<803f1f80>] (nand_write_page) from [<803f3bd8>] (nand_do_write_ops+0x240/0x444)
[   24.090180]  r8:00000400 r7:00000400 r6:9e674810 r5:803f1f80 r4:9e674b40
[   24.096970] [<803f3998>] (nand_do_write_ops) from [<803f3f94>] (nand_write+0x68/0x88)
[   24.104804]  r10:00000400 r9:00000000 r8:00580000 r7:9df42800 r6:9dcfdce8 r5:9dcfdc20
[   24.112719]  r4:9e674810
[   24.115287] [<803f3f2c>] (nand_write) from [<803eb63c>] (part_write+0x48/0x50)
[   24.122514]  r10:9d802000 r9:9dee1000 r8:9df42800 r7:00000000 r6:00000400 r5:00000000
[   24.130429]  r4:00580000
[   24.132989] [<803eb5f4>] (part_write) from [<803e82ac>] (mtd_write+0x88/0xa0)
[   24.140129]  r5:00000000 r4:803eb5f4
[   24.143748] [<803e8224>] (mtd_write) from [<80406048>] (ubi_io_write+0x104/0x65c)
[   24.151235]  r7:00000000 r6:00000400 r5:00000000 r4:9dee0000
[   24.156968] [<80405f44>] (ubi_io_write) from [<804066cc>] (ubi_io_write_ec_hdr+0x12c/0x190)
[   24.165323]  r10:9d802000 r9:9dc8b214 r8:00000000 r7:9d802030 r6:00000000 r5:9dee0000
[   24.173239]  r4:9df42800
[   24.175798] [<804065a0>] (ubi_io_write_ec_hdr) from [<8040a544>] (ubi_early_get_peb+0x110/0x1f0)
[   24.184587]  r6:9dc8b200 r5:9dee0000 r4:9df42800
[   24.189262] [<8040a434>] (ubi_early_get_peb) from [<803fb560>] (create_vtbl+0x7c/0x238)
[   24.197271]  r10:9dee0000 r9:9dc8b200 r8:9dc8b200 r7:9dc8b200 r6:00000080 r5:00000000
[   24.205187]  r4:9df42400
[   24.207746] [<803fb4e4>] (create_vtbl) from [<803fc08c>] (ubi_read_volume_table+0x750/0xa64)
[   24.216187]  r10:8112514c r9:9dc8b200 r8:a0acf000 r7:9dc8b200 r6:00000080 r5:00005600
[   24.224103]  r4:9dee0000
[   24.226662] [<803fb93c>] (ubi_read_volume_table) from [<8040afa0>] (ubi_attach+0x97c/0x152c)
[   24.235103]  r10:8112514c r9:9dc8b200 r8:00000001 r7:9dee0000 r6:00000065 r5:9dee0000
[   24.243018]  r4:00000000
[   24.245579] [<8040a624>] (ubi_attach) from [<803ff1bc>] (ubi_attach_mtd_dev+0x630/0xbac)
[   24.253673]  r10:9e7b5400 r9:00001000 r8:9dee1000 r7:9dee0000 r6:00000000 r5:9e7b5400
[   24.261588]  r4:fffff000
[   24.264148] [<803feb8c>] (ubi_attach_mtd_dev) from [<804008cc>] (ctrl_cdev_ioctl+0xcc/0x1cc)
[   24.272589]  r10:00000000 r9:9dcfc000 r8:00000003 r7:80113e30 r6:9e7b5400 r5:7e87ab70
[   24.280505]  r4:00000000
[   24.283070] [<80400800>] (ctrl_cdev_ioctl) from [<80113b5c>] (do_vfs_ioctl+0x42c/0x6c4)
[   24.291077]  r6:9dd92140 r5:7e87ab70 r4:9dc193e0
[   24.295753] [<80113730>] (do_vfs_ioctl) from [<80113e30>] (SyS_ioctl+0x3c/0x64)
[   24.303066]  r10:00000000 r9:9dcfc000 r8:7e87ab70 r7:40186f40 r6:9dd92140 r5:00000003
[   24.310981]  r4:9dd92140
[   24.313549] [<80113df4>] (SyS_ioctl) from [<8000f9a0>] (ret_fast_syscall+0x0/0x54)
[   24.321123]  r9:9dcfc000 r8:8000fb84 r7:00000036 r6:7e87aea9 r5:7e87ab70 r4:7e87ab70
[   24.328957] Code: e1c300b0 e1510002 e1a03001 1afffff9 (e89da800)
[   24.335066] ---[ end trace ab1cb17887f21bbb ]---
[   24.340249] Unhandled fault: imprecise external abort (0x1c06) at 0x7ee8bcf0
[   24.347310] pgd = 9df3c000
[   24.350023] [7ee8bcf0] *pgd=8dcbf831, *pte=8eb3334f, *ppte=8eb3383f
Segmentation fault

Fixes: 35d5d20 ("mtd: mxc_nand: cleanup copy_spare function")
Signed-off-by: Eric Bénard <[email protected]>
Reviewed-by: Uwe Kleine-König <[email protected]>
Reviewed-by: Baruch Siach <[email protected]>
Cc: <[email protected]>
Signed-off-by: Brian Norris <[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]>
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 Apr 24, 2017
commit 4dfce57 upstream.

There have been several reports over the years of NULL pointer
dereferences in xfs_trans_log_inode during xfs_fsr processes,
when the process is doing an fput and tearing down extents
on the temporary inode, something like:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
PID: 29439  TASK: ffff880550584fa0  CPU: 6   COMMAND: "xfs_fsr"
    [exception RIP: xfs_trans_log_inode+0x10]
 96boards#9 [ffff8800a57bbbe0] xfs_bunmapi at ffffffffa037398e [xfs]
96boards#10 [ffff8800a57bbce8] xfs_itruncate_extents at ffffffffa0391b29 [xfs]
96boards#11 [ffff8800a57bbd88] xfs_inactive_truncate at ffffffffa0391d0c [xfs]
96boards#12 [ffff8800a57bbdb8] xfs_inactive at ffffffffa0392508 [xfs]
96boards#13 [ffff8800a57bbdd8] xfs_fs_evict_inode at ffffffffa035907e [xfs]
96boards#14 [ffff8800a57bbe00] evict at ffffffff811e1b67
96boards#15 [ffff8800a57bbe28] iput at ffffffff811e23a5
#16 [ffff8800a57bbe58] dentry_kill at ffffffff811dcfc8
#17 [ffff8800a57bbe88] dput at ffffffff811dd06c
#18 [ffff8800a57bbea8] __fput at ffffffff811c823b
#19 [ffff8800a57bbef0] ____fput at ffffffff811c846e
#20 [ffff8800a57bbf00] task_work_run at ffffffff81093b27
96boards#21 [ffff8800a57bbf30] do_notify_resume at ffffffff81013b0c
96boards#22 [ffff8800a57bbf50] int_signal at ffffffff8161405d

As it turns out, this is because the i_itemp pointer, along
with the d_ops pointer, has been overwritten with zeros
when we tear down the extents during truncate.  When the in-core
inode fork on the temporary inode used by xfs_fsr was originally
set up during the extent swap, we mistakenly looked at di_nextents
to determine whether all extents fit inline, but this misses extents
generated by speculative preallocation; we should be using if_bytes
instead.

This mistake corrupts the in-memory inode, and code in
xfs_iext_remove_inline eventually gets bad inputs, causing
it to memmove and memset incorrect ranges; this became apparent
because the two values in ifp->if_u2.if_inline_ext[1] contained
what should have been in d_ops and i_itemp; they were memmoved due
to incorrect array indexing and then the original locations
were zeroed with memset, again due to an array overrun.

Fix this by properly using i_df.if_bytes to determine the number
of extents, not di_nextents.

Thanks to dchinner for looking at this with me and spotting the
root cause.

[nborisov: backported to 4.4]

Cc: [email protected]
Signed-off-by: Eric Sandeen <[email protected]>
Reviewed-by: Brian Foster <[email protected]>
Signed-off-by: Dave Chinner <[email protected]>
Signed-off-by: Nikolay Borisov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
--
 fs/xfs/xfs_bmap_util.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
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3 participants