INFO: task hung in lock_sock_nested (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 62872f95 Merge 4.4.174 into android-4.4
git tree: android-4.4
console output: https://syzkaller.appspot.com/x/log.txt?x=1497c8ea600000
kernel config: https://syzkaller.appspot.com/x/.config?x=47bc4dd423780c4a
dashboard link: https://syzkaller.appspot.com/bug?extid=4c32769d8282027eb12f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
userspace arch: i386

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4c3276...@syzkaller.appspotmail.com

lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'init' (1) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
INFO: task syz-executor.5:330 blocked for more than 140 seconds.
Not tainted 4.4.174+ #17
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5 D ffff88017b37fb08 30288 330 2097 0x20020004
ffff88017b37fb08 0000000000000002 ffff88017b37fb38 ffffffff811e9901
ffff8801d9e60000 ffffffff810e1700 ffff8801db71f180 ffff8801db71f1a8
ffff8801db71e898 ffff880164b6af80 ffff8801d9e60000 ffffed002f66f001
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'syz-executor.5' (337) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'cron' (1972) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved

Call Trace:
[<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
[<ffffffff821e4dae>] __lock_sock+0xfe/0x190 net/core/sock.c:2000
[<ffffffff821e4f36>] lock_sock_nested+0xf6/0x120 net/core/sock.c:2457
[<ffffffff826d527d>] lock_sock include/net/sock.h:1497 [inline]
[<ffffffff826d527d>] packet_setsockopt+0x84d/0x26c0
net/packet/af_packet.c:3703
[<ffffffff822ac3a3>] C_SYSC_setsockopt net/compat.c:388 [inline]
[<ffffffff822ac3a3>] compat_SyS_setsockopt+0x253/0x720 net/compat.c:368
[<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330
[inline]
[<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90
arch/x86/entry/common.c:397
[<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a
no locks held by syz-executor.5/330.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #17
task: ffff8801da6f2f80 task.stack: ffff8801d9ef0000
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>] _flat_send_IPI_mask
arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>]
flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0000:ffff8801d9ef7c88 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8801d9ef7cb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcea03ef08 CR3: 00000001d76ee000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
000000000001b6c0 0000000000000008 ffff8801d9ef7cd8 ffffffff81092bee
0000000000000008 ffffffff82924260 ffff8801d9ef7d30 ffffffff81ab8252
Call Trace:
[<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80
arch/x86/kernel/apic/hw_nmi.c:33
[<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae
lib/nmi_backtrace.c:85
[<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20
arch/x86/kernel/apic/hw_nmi.c:38
[<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44
[inline]
[<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff813b4762>] check_hung_uninterruptible_tasks
kernel/hung_task.c:182 [inline]
[<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
[<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'kworker/u4:15' (30312) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
[<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89
fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00
02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1
NMI backtrace for cpu 1
CPU: 1 PID: 394 Comm: init Not tainted 4.4.174+ #17
task: ffff88015b942f80 task.stack: ffff88005bf38000
RIP: 0010:[<ffffffff812006d9>] [<ffffffff812006d9>] hlock_class
kernel/locking/lockdep.c:142 [inline]
RIP: 0010:[<ffffffff812006d9>] [<ffffffff812006d9>] lookup_chain_cache
kernel/locking/lockdep.c:2019 [inline]
RIP: 0010:[<ffffffff812006d9>] [<ffffffff812006d9>] validate_chain
kernel/locking/lockdep.c:2115 [inline]
RIP: 0010:[<ffffffff812006d9>] [<ffffffff812006d9>]
__lock_acquire+0x1129/0x4f50 kernel/locking/lockdep.c:3213
RSP: 0000:ffff88005bf3f220 EFLAGS: 00000802
RAX: 0000000000000000 RBX: 000113810803a06c RCX: 0000000000000001
RDX: 1ffff1002b72871c RSI: ffff88015b943848 RDI: ffff88015b9438e1
RBP: ffff88005bf3f398 R08: 0000000000000003 R09: ffff88015b9438e0
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88015b942f80
R13: ffff88015b9438c0 R14: 0000000000000000 R15: 0000000000000000
FS: 00007ff02dec07a0(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff02da6b930 CR3: 00000001301b1000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
0000000000000000 0000000000000000 ffff88005bf3f3b8 0000000000000046
0000000000000000 0000000000000000 ffff88005bf3f3d8 ffffffff811fffff
ffff88015b9438d8 ffff88015b943840 ffff88015b9438e0 0000000000000000
Call Trace:
[<ffffffff8120687b>] __lock_release kernel/locking/lockdep.c:3439 [inline]
[<ffffffff8120687b>] lock_release+0x61b/0xcf0 kernel/locking/lockdep.c:3611
[<ffffffff813c293e>] rcu_lock_release include/linux/rcupdate.h:482 [inline]
[<ffffffff813c293e>] rcu_read_unlock include/linux/rcupdate.h:917 [inline]
[<ffffffff813c293e>] find_lock_task_mm+0x15e/0x280 mm/oom_kill.c:116
[<ffffffff8211e7cb>] lowmem_scan+0x45b/0xbf0
drivers/staging/android/lowmemorykiller.c:132
[<ffffffff813ee8e2>] do_shrink_slab mm/vmscan.c:357 [inline]
[<ffffffff813ee8e2>] shrink_slab.part.0+0x402/0xb30 mm/vmscan.c:455
[<ffffffff813f742c>] shrink_slab mm/vmscan.c:425 [inline]
[<ffffffff813f742c>] shrink_zone+0x4bc/0x610 mm/vmscan.c:2448
[<ffffffff813f7bef>] shrink_zones mm/vmscan.c:2603 [inline]
[<ffffffff813f7bef>] do_try_to_free_pages mm/vmscan.c:2653 [inline]
[<ffffffff813f7bef>] try_to_free_pages+0x66f/0x1260 mm/vmscan.c:2861
[<ffffffff813d09af>] __perform_reclaim mm/page_alloc.c:2915 [inline]
[<ffffffff813d09af>] __alloc_pages_direct_reclaim mm/page_alloc.c:2936
[inline]
[<ffffffff813d09af>] __alloc_pages_slowpath mm/page_alloc.c:3201 [inline]
[<ffffffff813d09af>] __alloc_pages_nodemask+0x8af/0x14b0
mm/page_alloc.c:3313
[<ffffffff8142fc53>] __alloc_pages include/linux/gfp.h:415 [inline]
[<ffffffff8142fc53>] __alloc_pages_node include/linux/gfp.h:428 [inline]
[<ffffffff8142fc53>] alloc_pages_node include/linux/gfp.h:442 [inline]
[<ffffffff8142fc53>] wp_page_copy.isra.0+0x113/0xc70 mm/memory.c:2167
[<ffffffff81433bda>] do_wp_page+0x23a/0x1340 mm/memory.c:2441
[<ffffffff8143b2e4>] handle_pte_fault mm/memory.c:3362 [inline]
[<ffffffff8143b2e4>] __handle_mm_fault mm/memory.c:3474 [inline]
[<ffffffff8143b2e4>] handle_mm_fault+0x1614/0x3140 mm/memory.c:3503
[<ffffffff810aaa4e>] __do_page_fault+0x28e/0x7f0 arch/x86/mm/fault.c:1243
[<ffffffff810ab008>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1306
[<ffffffff82719e35>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:1064
Code: 83 41 22 10 c7 84 24 80 00 00 00 01 00 00 00 e9 81 f4 ff ff 48 b8 00
00 00 00 00 fc ff df 48 8b 54 24 50 48 c1 ea 03 0f b6 04 02 <84> c0 74 0e
3c 01 7f 0a 48 8b 7c 24 50 e8 95 47 28 00 49 bf eb
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'syz-fuzzer' (17030) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'syz-fuzzer' (2069) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'rsyslogd' (1919) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'cron' (1972) because
cache 964kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'init' (1) because
cache 820kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (341) (tgid 334), adj 1000,
to free 51392kB on behalf of 'init' (394) because
cache 820kB is below limit 6144kB for oom_score_adj 0
Free memory is 2932kB above reserved


---
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.