syzbot


WARNING: locking bug in copy_process

Status: fixed on 2019/06/14 18:22
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+3286e58549edc479faae@syzkaller.appspotmail.com
Fix commit: c3b7112df86b fork: do not release lock that wasn't taken
First crash: 1869d, last: 1867d
Cause bisection: introduced by (bisect log) :
commit b3e5838252665ee4cfa76b82bdf1198dca81e5be
Author: Christian Brauner <christian@brauner.io>
Date: Wed Mar 27 12:04:15 2019 +0000

  clone: add CLONE_PIDFD

Crash: WARNING: locking bug in copy_process (log)
Repro: C syz .config
  
Discussions (3)
Title Replies (including bot) Last reply
[PATCH] fork: do not release lock that wasn't taken 5 (5) 2019/05/10 19:14
[GIT PULL] pidfd fixes for v5.2-rc1 2 (2) 2019/05/10 17:35
WARNING: locking bug in copy_process 1 (2) 2019/05/10 05:09
Last patch testing requests (2)
Created Duration User Patch Repo Result
2019/05/13 12:13 21m syzkaller-bugs@googlegroups.com git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git pidfd OK
2019/05/10 11:54 23m christian@brauner.io git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git pidfd OK

Sample crash report:
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fec849
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000ffed5a8c EFLAGS: 00000246 ORIG_RAX: 0000000000000078
RAX: ffffffffffffffda RBX: 0000000000003ffc RCX: 0000000000000000
RDX: 00000000200005c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000012 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(depth <= 0)
WARNING: CPU: 1 PID: 7744 at kernel/locking/lockdep.c:4052 __lock_release kernel/locking/lockdep.c:4052 [inline]
WARNING: CPU: 1 PID: 7744 at kernel/locking/lockdep.c:4052 lock_release+0x667/0xa00 kernel/locking/lockdep.c:4321
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 7744 Comm: syz-executor007 Not tainted 5.1.0+ #4
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+0x172/0x1f0 lib/dump_stack.c:113
 panic+0x2cb/0x65c kernel/panic.c:214
 __warn.cold+0x20/0x45 kernel/panic.c:566
 report_bug+0x263/0x2b0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:972
RIP: 0010:__lock_release kernel/locking/lockdep.c:4052 [inline]
RIP: 0010:lock_release+0x667/0xa00 kernel/locking/lockdep.c:4321
Code: 0f 85 a0 03 00 00 8b 35 77 66 08 08 85 f6 75 23 48 c7 c6 a0 55 6b 87 48 c7 c7 40 25 6b 87 4c 89 85 70 ff ff ff e8 b7 a9 eb ff <0f> 0b 4c 8b 85 70 ff ff ff 4c 89 ea 4c 89 e6 4c 89 c7 e8 52 63 ff
RSP: 0018:ffff888094117b48 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 1ffff11012822f6f RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815af236 RDI: ffffed1012822f5b
RBP: ffff888094117c00 R08: ffff888092bfc400 R09: fffffbfff113301d
R10: fffffbfff113301c R11: ffffffff889980e3 R12: ffffffff8a451df8
R13: ffffffff8142e71f R14: ffffffff8a44cc80 R15: ffff888094117bd8
 percpu_up_read.constprop.0+0xcb/0x110 include/linux/percpu-rwsem.h:92
 cgroup_threadgroup_change_end include/linux/cgroup-defs.h:712 [inline]
 copy_process.part.0+0x47ff/0x6710 kernel/fork.c:2222
 copy_process kernel/fork.c:1772 [inline]
 _do_fork+0x25d/0xfd0 kernel/fork.c:2338
 __do_compat_sys_x86_clone arch/x86/ia32/sys_ia32.c:240 [inline]
 __se_compat_sys_x86_clone arch/x86/ia32/sys_ia32.c:236 [inline]
 __ia32_compat_sys_x86_clone+0xbc/0x140 arch/x86/ia32/sys_ia32.c:236
 do_syscall_32_irqs_on arch/x86/entry/common.c:334 [inline]
 do_fast_syscall_32+0x281/0xd54 arch/x86/entry/common.c:405
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fec849
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000ffed5a8c EFLAGS: 00000246 ORIG_RAX: 0000000000000078
RAX: ffffffffffffffda RBX: 0000000000003ffc RCX: 0000000000000000
RDX: 00000000200005c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000012 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/05/09 18:05 upstream a2d635decbfa 6fc130d3 .config console log report syz C ci-upstream-kasan-gce-386
2019/05/09 17:24 upstream a2d635decbfa 6fc130d3 .config console log report ci-upstream-kasan-gce-386
2019/05/12 07:52 linux-next a802303934b3 c017728b .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.