syzbot


WARNING: refcount bug in call_timer_fn

Status: closed as invalid on 2022/01/07 18:56
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 356d, last: 356d

Sample crash report:
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 13128 at lib/refcount.c:28 refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 1 PID: 13128 Comm: syz-executor.3 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
Code: c7 c0 00 d5 8a 31 c0 e8 43 3e 38 fd 0f 0b eb 85 e8 2a 65 6e fd c6 05 f4 23 d5 09 01 48 c7 c7 20 01 d5 8a 31 c0 e8 25 3e 38 fd <0f> 0b e9 64 ff ff ff e8 09 65 6e fd c6 05 d4 23 d5 09 01 48 c7 c7
RSP: 0018:ffffc90000dc0c48 EFLAGS: 00010246
RAX: 3029cfd0e2f13c00 RBX: 0000000000000003 RCX: ffff888021a98000
RDX: 0000000000000101 RSI: 0000000000000101 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff816a0e02 R09: ffffed10173667b1
R10: ffffed10173667b1 R11: 0000000000000000 R12: ffff8880625921b8
R13: ffffc90000dc0ca0 R14: 0000000000000101 R15: 1ffff920001b8190
FS:  00007f1f92e63700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff20d885000 CR3: 0000000071d9a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 call_timer_fn+0xf6/0x210 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers+0x71a/0x910 kernel/time/timer.c:1734
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1747
 __do_softirq+0x392/0x7a3 kernel/softirq.c:558
 do_softirq+0x161/0x240 kernel/softirq.c:459
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1b0/0x1f0 kernel/softirq.c:383
 rcu_read_unlock_bh include/linux/rcupdate.h:758 [inline]
 ip6_finish_output2+0xf7a/0x14c0 net/ipv6/ip6_output.c:127
 ip6_fragment+0x1ff1/0x27f0 net/ipv6/ip6_output.c:966
 ip6_send_skb+0x109/0x220 net/ipv6/ip6_output.c:1912
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x2ee6/0x4320 net/ipv6/raw.c:956
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 ____sys_sendmsg+0x5b9/0x910 net/socket.c:2409
 ___sys_sendmsg net/socket.c:2463 [inline]
 __sys_sendmsg+0x280/0x370 net/socket.c:2492
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f1f93eedae9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1f92e63188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1f94000f60 RCX: 00007f1f93eedae9
RDX: 000000000000350c RSI: 0000000020000a40 RDI: 000000000000000f
RBP: 00007f1f93f47ff7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff55c89cef R14: 00007f1f92e63300 R15: 0000000000022000
 </TASK>

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/12/05 04:53 upstream bbef3c7a63d2 a617004c .config log report info WARNING: refcount bug in call_timer_fn
* Struck through repros no longer work on HEAD.