#syz dup: WARNING: suspicious RCU usage in getname_flags
On Fri, Apr 02, 2021 at 07:52:17PM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:1e43c377 Merge tag 'xtensa-20210329' of git://github.com/j..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16d76301d0
> kernel config: https://syzkaller.appspot.com/x/.config?x=78ef1d159159890
> dashboard link: https://syzkaller.appspot.com/bug?extid=bdef67a6b28a89e6fe71
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+bdef67a6b28a89e6f...@syzkaller.appspotmail.com
>
> =
> WARNING: suspicious RCU usage
> 5.12.0-rc5-syzkaller #0 Not tainted
> -
> kernel/sched/core.c:8294 Illegal context switch in RCU-bh read-side critical
> section!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 2, debug_locks = 0
> no locks held by systemd-udevd/4825.
>
> stack backtrace:
> CPU: 1 PID: 4825 Comm: systemd-udevd Not tainted 5.12.0-rc5-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:79 [inline]
> dump_stack+0x141/0x1d7 lib/dump_stack.c:120
> ___might_sleep+0x229/0x2c0 kernel/sched/core.c:8294
> dput+0x4d/0xbc0 fs/dcache.c:870
> step_into+0x2cf/0x1c80 fs/namei.c:1778
> walk_component+0x171/0x6a0 fs/namei.c:1945
> link_path_walk.part.0+0x712/0xc90 fs/namei.c:2266
> link_path_walk fs/namei.c:2190 [inline]
> path_lookupat+0xb7/0x830 fs/namei.c:2419
> filename_lookup+0x19f/0x560 fs/namei.c:2453
> do_readlinkat+0xcd/0x2f0 fs/stat.c:417
> __do_sys_readlinkat fs/stat.c:444 [inline]
> __se_sys_readlinkat fs/stat.c:441 [inline]
> __x64_sys_readlinkat+0x93/0xf0 fs/stat.c:441
> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7fb5a7e200ba
> Code: 48 8b 0d e1 bd 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00
> 00 00 00 0f 1f 44 00 00 49 89 ca b8 0b 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73
> 01 c3 48 8b 0d ae bd 2b 00 f7 d8 64 89 01 48
> RSP: 002b:7ffc9c440e38 EFLAGS: 0202 ORIG_RAX: 010b
> RAX: ffda RBX: 5604089e4380 RCX: 7fb5a7e200ba
> RDX: 5604089e4380 RSI: 7ffc9c440ec0 RDI: ff9c
> RBP: 0064 R08: 7fb5a80dcbc8 R09: 0070
> R10: 0063 R11: 0202 R12: 7ffc9c440ec0
> R13: ff9c R14: 7ffc9c440e90 R15: 0063
>
>
> ---
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>
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