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* KCSAN: data-race in taskstats_exit / taskstats_exit
@ 2019-10-05  4:26 syzbot
  2019-10-05  4:29 ` Dmitry Vyukov
                   ` (2 more replies)
  0 siblings, 3 replies; 62+ messages in thread
From: syzbot @ 2019-10-05  4:26 UTC (permalink / raw)
  To: bsingharora, elver, linux-kernel, syzkaller-bugs

Hello,

syzbot found the following crash on:

HEAD commit:    b4bd9343 x86, kcsan: Enable KCSAN for x86
git tree:       https://github.com/google/ktsan.git kcsan
console output: https://syzkaller.appspot.com/x/log.txt?x=125329db600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c0906aa620713d80
dashboard link: https://syzkaller.appspot.com/bug?extid=c5d03165a1bd1dead0c1
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

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+c5d03165a1bd1dead0c1@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in taskstats_exit / taskstats_exit

write to 0xffff8881157bbe10 of 8 bytes by task 7951 on cpu 0:
  taskstats_tgid_alloc kernel/taskstats.c:567 [inline]
  taskstats_exit+0x6b7/0x717 kernel/taskstats.c:596
  do_exit+0x2c2/0x18e0 kernel/exit.c:864
  do_group_exit+0xb4/0x1c0 kernel/exit.c:983
  get_signal+0x2a2/0x1320 kernel/signal.c:2734
  do_signal+0x3b/0xc00 arch/x86/kernel/signal.c:815
  exit_to_usermode_loop+0x250/0x2c0 arch/x86/entry/common.c:159
  prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
  syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
  do_syscall_64+0x2d7/0x2f0 arch/x86/entry/common.c:299
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881157bbe10 of 8 bytes by task 7949 on cpu 1:
  taskstats_tgid_alloc kernel/taskstats.c:559 [inline]
  taskstats_exit+0xb2/0x717 kernel/taskstats.c:596
  do_exit+0x2c2/0x18e0 kernel/exit.c:864
  do_group_exit+0xb4/0x1c0 kernel/exit.c:983
  __do_sys_exit_group kernel/exit.c:994 [inline]
  __se_sys_exit_group kernel/exit.c:992 [inline]
  __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:992
  do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7949 Comm: syz-executor.3 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 7949 Comm: syz-executor.3 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0xf5/0x159 lib/dump_stack.c:113
  panic+0x209/0x639 kernel/panic.c:219
  end_report kernel/kcsan/report.c:135 [inline]
  kcsan_report.cold+0x57/0xeb kernel/kcsan/report.c:283
  __kcsan_setup_watchpoint+0x342/0x500 kernel/kcsan/core.c:456
  __tsan_read8 kernel/kcsan/kcsan.c:31 [inline]
  __tsan_read8+0x2c/0x30 kernel/kcsan/kcsan.c:31
  taskstats_tgid_alloc kernel/taskstats.c:559 [inline]
  taskstats_exit+0xb2/0x717 kernel/taskstats.c:596
  do_exit+0x2c2/0x18e0 kernel/exit.c:864
  do_group_exit+0xb4/0x1c0 kernel/exit.c:983
  __do_sys_exit_group kernel/exit.c:994 [inline]
  __se_sys_exit_group kernel/exit.c:992 [inline]
  __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:992
  do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x459a59
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc4ccf3408 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000000000000001e RCX: 0000000000459a59
RDX: 0000000000413741 RSI: fffffffffffffff7 RDI: 0000000000000000
RBP: 0000000000000000 R08: 000000007f8e4506 R09: 00007ffc4ccf3460
R10: ffffffff81007108 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc4ccf3460 R14: 0000000000000000 R15: 00007ffc4ccf3470
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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^ permalink raw reply	[flat|nested] 62+ messages in thread

end of thread, other threads:[~2019-11-30 15:09 UTC | newest]

Thread overview: 62+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-05  4:26 KCSAN: data-race in taskstats_exit / taskstats_exit syzbot
2019-10-05  4:29 ` Dmitry Vyukov
2019-10-05 11:29   ` Christian Brauner
2019-10-05 11:28 ` [PATCH] taskstats: fix data-race Christian Brauner
2019-10-05 13:33   ` Marco Elver
2019-10-05 14:15     ` Christian Brauner
2019-10-05 14:34       ` Marco Elver
2019-10-06 10:00   ` Dmitry Vyukov
2019-10-06 10:59     ` Christian Brauner
2019-10-06 23:52   ` Christian Brauner
2019-10-07  7:31     ` Dmitry Vyukov
2019-10-07  9:29       ` Christian Brauner
2019-10-07 10:40     ` Andrea Parri
2019-10-07 10:50       ` Christian Brauner
2019-10-07 11:01       ` [PATCH v2] " Christian Brauner
2019-10-07 13:18         ` Andrea Parri
2019-10-07 13:28           ` Christian Brauner
2019-10-07 13:50           ` Dmitry Vyukov
2019-10-07 13:55             ` Christian Brauner
2019-10-07 14:08               ` Dmitry Vyukov
2019-10-07 14:10                 ` Christian Brauner
2019-10-07 14:14             ` Andrea Parri
2019-10-07 14:18               ` Dmitry Vyukov
2019-10-08 14:20                 ` Andrea Parri
2019-10-08 14:24                   ` Christian Brauner
2019-10-08 15:26                     ` Andrea Parri
2019-10-08 15:35                       ` Christian Brauner
2019-10-08 15:44                         ` Andrea Parri
2019-10-09 11:31                           ` [PATCH] " Christian Brauner
2019-10-09 11:40                             ` Christian Brauner
2019-10-09 11:48                             ` [PATCH v5] " Christian Brauner
2019-10-09 12:08                               ` Andrea Parri
2019-10-09 13:26                               ` Christian Brauner
2019-10-21 11:33                               ` [PATCH v6] " Christian Brauner
2019-10-21 12:19                                 ` Rasmus Villemoes
2019-10-21 13:04                                   ` Christian Brauner
2019-11-29 17:56                                     ` Will Deacon
2019-11-30 15:08                                       ` Christian Brauner
2019-10-23 12:16                                 ` Andrea Parri
2019-10-23 12:39                                   ` Dmitry Vyukov
2019-10-23 13:11                                     ` Christian Brauner
2019-10-23 13:20                                       ` Dmitry Vyukov
2019-10-24 11:31                                     ` Andrea Parri
2019-10-24 11:51                                       ` Dmitry Vyukov
2019-10-24 13:05                                         ` Andrea Parri
2019-10-24 13:13                                           ` Dmitry Vyukov
2019-10-24 13:21                                             ` Christian Brauner
2019-10-24 13:34                                               ` Dmitry Vyukov
2019-10-24 13:43                                             ` Andrea Parri
2019-10-24 13:58                                               ` Dmitry Vyukov
2019-10-24 14:40                                                 ` Andrea Parri
2019-10-24 14:49                                                   ` Dmitry Vyukov
2019-11-29 17:57                                 ` Will Deacon
2019-10-09 11:48                             ` [PATCH] " Marco Elver
2019-10-09 11:53                               ` Christian Brauner
2019-11-06  0:27   ` Balbir Singh
2019-11-06  0:09 ` KCSAN: data-race in taskstats_exit / taskstats_exit Balbir Singh
2019-11-06 10:23   ` Marco Elver
2019-11-07 10:39     ` Balbir Singh
2019-11-08  0:54     ` Balbir Singh
2019-11-08  8:55       ` Dmitry Vyukov
2019-11-09  3:42         ` Balbir Singh

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