Messages in this thread | | | Date | Mon, 05 Aug 2019 10:52:07 -0700 | Subject | WARNING: refcount bug in blk_mq_free_request (2) | From | syzbot <> |
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Hello,
syzbot found the following crash on:
HEAD commit: e21a712a Linux 5.3-rc3 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10cf349a600000 kernel config: https://syzkaller.appspot.com/x/.config?x=a4c9e9f08e9e8960 dashboard link: https://syzkaller.appspot.com/bug?extid=f4316dab9d4518b755eb compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=117a1906600000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11aa11aa600000
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+f4316dab9d4518b755eb@syzkaller.appspotmail.com
------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 16 at lib/refcount.c:190 refcount_sub_and_test_checked lib/refcount.c:190 [inline] WARNING: CPU: 1 PID: 16 at lib/refcount.c:190 refcount_sub_and_test_checked+0x1d0/0x200 lib/refcount.c:180 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.3.0-rc3 #98 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+0x2dc/0x755 kernel/panic.c:219 __warn.cold+0x20/0x4c 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+0x23/0x30 arch/x86/entry/entry_64.S:1026 RIP: 0010:refcount_sub_and_test_checked lib/refcount.c:190 [inline] RIP: 0010:refcount_sub_and_test_checked+0x1d0/0x200 lib/refcount.c:180 Code: 1d 7e b3 64 06 31 ff 89 de e8 9c a3 35 fe 84 db 75 94 e8 53 a2 35 fe 48 c7 c7 80 02 c6 87 c6 05 5e b3 64 06 01 e8 18 15 07 fe <0f> 0b e9 75 ff ff ff e8 34 a2 35 fe e9 6e ff ff ff 48 89 df e8 b7 RSP: 0018:ffff8880a990fbb0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000100 RSI: ffffffff815c3ba6 RDI: ffffed1015321f68 RBP: ffff8880a990fc48 R08: ffff8880a9900440 R09: ffffed1015d24101 R10: ffffed1015d24100 R11: ffff8880ae920807 R12: 00000000ffffffff R13: 0000000000000001 R14: ffff8880a990fc20 R15: 0000000000000000 refcount_dec_and_test_checked+0x1b/0x20 lib/refcount.c:220 blk_mq_free_request+0x3b8/0x580 block/blk-mq.c:524 __blk_mq_end_request block/blk-mq.c:550 [inline] blk_mq_end_request+0x456/0x560 block/blk-mq.c:559 nbd_complete_rq+0x42/0x50 drivers/block/nbd.c:322 blk_done_softirq+0x2fe/0x4d0 block/blk-softirq.c:37 __do_softirq+0x262/0x98c kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:603 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Kernel Offset: disabled Rebooting in 86400 seconds..
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