On Thu, Dec 28, 2017 at 2:58 PM, Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> wrote: > On Thu, Dec 28, 2017 at 10:30:46AM +0100, Dmitry Vyukov wrote: >> On Thu, Dec 28, 2017 at 10:20 AM, syzbot >> <syzbot+aa0386edb3e128ffa315@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >> > Hello, >> > >> > syzkaller hit the following crash on >> > 82bcf1def3b5f1251177ad47c44f7e17af039b4b >> > git://git.cmpxchg.org/linux-mmots.git/master >> > compiler: gcc (GCC) 7.1.1 20170620 >> > .config is attached >> > Raw console output is attached. >> > C reproducer is attached >> > syzkaller reproducer is attached. See https://goo.gl/kgGztJ >> > for information about syzkaller reproducers >> > >> > >> > IMPORTANT: if you fix the bug, please add the following tag to the commit: >> > Reported-by: syzbot+aa0386edb3e128ffa315@xxxxxxxxxxxxxxxxxxxxxxxxx >> > It will help syzbot understand when the bug is fixed. See footer for >> > details. >> > If you forward the report, please keep this part and the footer. >> > >> > audit: type=1400 audit(1513711793.237:7): avc: denied { map } for >> > pid=3151 comm="syzkaller173649" path="/root/syzkaller173649879" dev="sda1" >> > ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 >> > tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 >> > WARNING: CPU: 1 PID: 3151 at kernel/sched/wait.c:79 >> > __wake_up_common+0x433/0x770 kernel/sched/wait.c:79 >> > Kernel panic - not syncing: panic_on_warn set ... >> > >> > CPU: 1 PID: 3151 Comm: syzkaller173649 Not tainted 4.15.0-rc2-mm1+ #39 >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> > Google 01/01/2011 >> > Call Trace: >> > __dump_stack lib/dump_stack.c:17 [inline] >> > dump_stack+0x194/0x257 lib/dump_stack.c:53 >> > panic+0x1e4/0x41c kernel/panic.c:183 >> > __warn+0x1dc/0x200 kernel/panic.c:547 >> > report_bug+0x211/0x2d0 lib/bug.c:184 >> > fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:177 >> > fixup_bug arch/x86/kernel/traps.c:246 [inline] >> > do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:295 >> > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314 >> > invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1079 >> > RIP: 0010:__wake_up_common+0x433/0x770 kernel/sched/wait.c:79 >> > RSP: 0018:ffff8801c4897648 EFLAGS: 00010246 >> > RAX: 0000000000000000 RBX: ffff8801d8cbfe50 RCX: 0000000000000004 >> > RDX: 1ffffffff0c59731 RSI: ffff8801d8cbfe68 RDI: 0000000000000282 >> > RBP: ffff8801c4897748 R08: ffff8801c4897858 R09: 0000000000000000 >> > R10: 000000000000000b R11: ffffed0038912e48 R12: 0000000000000000 >> > R13: ffff8801d8cbfe00 R14: 0000000000000001 R15: ffff8801c4897858 >> > __wake_up_locked_key+0x16/0x20 kernel/sched/wait.c:166 >> > userfaultfd_release+0x4da/0x750 fs/userfaultfd.c:885 >> > __fput+0x333/0x7f0 fs/file_table.c:210 >> > ____fput+0x15/0x20 fs/file_table.c:244 >> > task_work_run+0x199/0x270 kernel/task_work.c:113 >> > exit_task_work include/linux/task_work.h:22 [inline] >> > do_exit+0x9bb/0x1ae0 kernel/exit.c:869 >> > do_group_exit+0x149/0x400 kernel/exit.c:972 >> > SYSC_exit_group kernel/exit.c:983 [inline] >> > SyS_exit_group+0x1d/0x20 kernel/exit.c:981 >> > entry_SYSCALL_64_fastpath+0x1f/0x96 >> > RIP: 0033:0x43e848 >> > RSP: 002b:00007ffe33766e08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 >> > RAX: ffffffffffffffda RBX: 00000000006ca800 RCX: 000000000043e848 >> > RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 >> > RBP: 00000000000014b1 R08: 00000000000000e7 R09: ffffffffffffffd0 >> > R10: 0000000000000006 R11: 0000000000000246 R12: 00000000006ca858 >> > R13: 00000000006ca858 R14: 0000000000000000 R15: 0000000000002710 >> > Dumping ftrace buffer: >> > (ftrace buffer empty) >> > Kernel Offset: disabled >> > Rebooting in 86400 seconds.. >> >> >> This was triggered by just creating a userfaultfd, and happened only >> in mmots but stopped happening few days ago. I don't see any recent >> commits touching useffaultfd.c in mm tree (other than >> "mm/userfaultfd.c: remove duplicate include"). Was a bogus commit >> dropped from mm tree? Let's close this bug for now and see if it >> happens again: > > Seems to me it's the same problem as one reported by 01day bot [1]. > > There was Christoph's patch "sched/wait: assert the wait_queue_head lock is > held in __wake_up_common" that Andrew dropped from his tree. > This patch revealed, hmm, special wait queue locking in the userfault. Thanks. Always good to know the actual root cause. So now 2 bots won't let it re-enter the tree if it breaks something :) > [1] https://lkml.org/lkml/2017/12/13/942 > >> #syz invalid >> >> >> > --- >> > This bug is generated by a dumb bot. It may contain errors. >> > See https://goo.gl/tpsmEJ for details. >> > Direct all questions to syzkaller@xxxxxxxxxxxxxxxx. >> > >> > syzbot will keep track of this bug report. >> > If you forgot to add the Reported-by tag, once the fix for this bug is >> > merged >> > into any tree, please reply to this email with: >> > #syz fix: exact-commit-title >> > If you want to test a patch for this bug, please reply with: >> > #syz test: git://repo/address.git branch >> > and provide the patch inline or as an attachment. >> > To mark this as a duplicate of another syzbot report, please reply with: >> > #syz dup: exact-subject-of-another-report >> > If it's a one-off invalid bug report, please reply with: >> > #syz invalid >> > Note: if the crash happens again, it will cause creation of a new bug >> > report. >> > Note: all commands must start from beginning of the line in the email body. >> > >> > -- >> > You received this message because you are subscribed to the Google Groups >> > "syzkaller-bugs" group. >> > To unsubscribe from this group and stop receiving emails from it, send an >> > email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. >> > To view this discussion on the web visit >> > https://groups.google.com/d/msgid/syzkaller-bugs/001a113f542a43cb1f05616305fb%40google.com. >> > For more options, visit https://groups.google.com/d/optout. >> >> -- >> To unsubscribe, send a message with 'unsubscribe linux-mm' in >> the body to majordomo@xxxxxxxxx. For more info on Linux MM, >> see: http://www.linux-mm.org/ . >> Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> >> > > -- > Sincerely yours, > Mike. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
