On 4/13/19 2:16 AM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: bcb67f0f Add linux-next specific files for 20190412 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=165912d3200000 > kernel config: https://syzkaller.appspot.com/x/.config?x=35c479ecf64ba753 > dashboard link: https://syzkaller.appspot.com/bug?extid=6d4a92619eb0ad08602b > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14c9ebbb200000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=153f76dd200000 > > The bug was bisected to: > > commit 6c271ce2f1d572f7fa225700a13cfe7ced492434 > Author: Jens Axboe <axboe@xxxxxxxxx> > Date: Thu Jan 10 18:22:30 2019 +0000 > > io_uring: add submission polling > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=143498f3200000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=163498f3200000 > console output: https://syzkaller.appspot.com/x/log.txt?x=123498f3200000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+6d4a92619eb0ad08602b@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 6c271ce2f1d5 ("io_uring: add submission polling") > > WARNING: CPU: 0 PID: 7822 at kernel/kthread.c:399 > __kthread_bind_mask+0x3b/0xc0 kernel/kthread.c:399 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 0 PID: 7822 Comm: syz-executor030 Not tainted 5.1.0-rc4-next-20190412 > #24 > 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/0x72b kernel/panic.c:214 > __warn.cold+0x20/0x46 kernel/panic.c:576 > 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:973 > RIP: 0010:__kthread_bind_mask+0x3b/0xc0 kernel/kthread.c:399 > Code: 48 89 fb e8 f7 ab 24 00 4c 89 e6 48 89 df e8 ac e1 02 00 31 ff 49 89 > c4 48 89 c6 e8 7f ad 24 00 4d 85 e4 75 15 e8 d5 ab 24 00 <0f> 0b e8 ce ab > 24 00 5b 41 5c 41 5d 41 5e 5d c3 e8 c0 ab 24 00 4c > RSP: 0018:ffff8880a89bfbb8 EFLAGS: 00010293 > RAX: ffff88808ca7a280 RBX: ffff8880a98e4380 RCX: ffffffff814bdd11 > RDX: 0000000000000000 RSI: ffffffff814bdd1b RDI: 0000000000000007 > RBP: ffff8880a89bfbd8 R08: ffff88808ca7a280 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > R13: ffffffff87691148 R14: ffff8880a98e43a0 R15: ffffffff81c91e10 > __kthread_bind kernel/kthread.c:412 [inline] > kthread_unpark+0x123/0x160 kernel/kthread.c:480 > kthread_stop+0xfa/0x6c0 kernel/kthread.c:556 > io_sq_thread_stop fs/io_uring.c:2057 [inline] > io_sq_thread_stop fs/io_uring.c:2052 [inline] > io_finish_async+0xab/0x180 fs/io_uring.c:2064 > io_ring_ctx_free fs/io_uring.c:2534 [inline] > io_ring_ctx_wait_and_kill+0x133/0x510 fs/io_uring.c:2591 > io_uring_release+0x42/0x50 fs/io_uring.c:2599 > __fput+0x2e5/0x8d0 fs/file_table.c:278 > ____fput+0x16/0x20 fs/file_table.c:309 > task_work_run+0x14a/0x1c0 kernel/task_work.c:113 > exit_task_work include/linux/task_work.h:22 [inline] > do_exit+0x90a/0x2fa0 kernel/exit.c:876 > do_group_exit+0x135/0x370 kernel/exit.c:980 > __do_sys_exit_group kernel/exit.c:991 [inline] > __se_sys_exit_group kernel/exit.c:989 [inline] > __x64_sys_exit_group+0x44/0x50 kernel/exit.c:989 > do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x43ee98 > Code: Bad RIP value. > RSP: 002b:00007fff28656a18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee98 > RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 > RBP: 00000000004be6a8 R08: 00000000000000e7 R09: ffffffffffffffd0 > R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000001 > R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 > Kernel Offset: disabled > Rebooting in 86400 seconds.. This should fix it. diff --git a/fs/io_uring.c b/fs/io_uring.c index 07d6ef195d05..06ee42cfb9c7 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1920,6 +1920,10 @@ static int io_sq_thread(void *data) unuse_mm(cur_mm); mmput(cur_mm); } + + if (kthread_should_park()) + kthread_parkme(); + return 0; } @@ -2054,6 +2058,7 @@ static void io_sq_thread_stop(struct io_ring_ctx *ctx) if (ctx->sqo_thread) { ctx->sqo_stop = 1; mb(); + kthread_park(ctx->sqo_thread); kthread_stop(ctx->sqo_thread); ctx->sqo_thread = NULL; } -- Jens Axboe
