general protection fault in rb_next (3)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 0011572c Merge branch 'for-5.2-fixes' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=147fbc56a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=fa9f7e1b6a8bb586
dashboard link: https://syzkaller.appspot.com/bug?extid=ab4c44191771d56c4eda
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17c17076a00000

The bug was bisected to:

commit e9db4ef6bf4ca9894bb324c76e01b8f1a16b2650
Author: John Fastabend <john.fa...@gmail.com>
Date: Sat Jun 30 13:17:47 2018 +0000

bpf: sockhash fix omitted bucket lock in sock_close

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14c090eaa00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=16c090eaa00000
console output: https://syzkaller.appspot.com/x/log.txt?x=12c090eaa00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ab4c44...@syzkaller.appspotmail.com
Fixes: e9db4ef6bf4c ("bpf: sockhash fix omitted bucket lock in sock_close")

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8856 Comm: syz-executor.2 Not tainted 5.2.0-rc4+ #32
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:rb_next+0xd7/0x140 lib/rbtree.c:529
Code: 49 89 dc 4c 89 eb 48 83 e3 fc 48 89 d8 75 c8 48 83 c4 08 5b 41 5c 41
5d 41 5e 5d c3 48 89 d0 48 8d 78 10 48 89 fa 48 c1 ea 03 <80> 3c 1a 00 75
1a 48 8b 50 10 48 85 d2 75 e3 48 83 c4 08 5b 41 5c
RSP: 0018:ffff8880ae809d70 EFLAGS: 00010007
RAX: 26f1e8c689c389ff RBX: dffffc0000000000 RCX: ffffffff87185c81
RDX: 04de3d18d1387141 RSI: ffffffff87185d10 RDI: 26f1e8c689c38a0f
RBP: ffff8880ae809d98 R08: ffff88808a51a440 R09: ffffed1015d06be0
R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: ffff8880ae8275c0
R13: ffff8880ae827861 R14: dffffc0000000000 R15: ffff8880ae826d00
FS: 0000555555728940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000a8dc78 CR3: 00000000992f7000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
timerqueue_del+0xd8/0x150 lib/timerqueue.c:70
__remove_hrtimer+0xa8/0x1c0 kernel/time/hrtimer.c:975
__run_hrtimer kernel/time/hrtimer.c:1371 [inline]
__hrtimer_run_queues+0x2a8/0xdd0 kernel/time/hrtimer.c:1451
hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1066
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
</IRQ>
Modules linked in:

======================================================


---
This bug is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Eric Biggers]

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#syz fix: bpf: sockmap/tls, close can race with map free