Re: [PATCH] fuse: add a null-ptr check

From: Bernd Schubert
Date: Mon Dec 02 2024 - 16:17:56 EST


Btw, totally unrelated to the report, but related to what the C
reproducer does, killing it sometimes results in

12563 pts/1 Zl 0:00 [syzkaller] <defunct>


[ 46.018014] mount.nfs (1163) used greatest stack depth: 23944 bytes left
[ 9929.865478] syzkaller (12313) used greatest stack depth: 23216 bytes left
[10159.658915] INFO: task syzkaller:12312 blocked for more than 120 seconds.
[10159.663075] Not tainted 6.13.0-rc1+ #92
[10159.665618] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[10159.673650] task:syzkaller state:D stack:28944 pid:12312 tgid:12307 ppid:1 flags:0x00004006
[10159.681276] Call Trace:
[10159.683004] <TASK>
[10159.685636] __schedule+0x1b42/0x25b0
[10159.688521] schedule+0xb5/0x260
[10159.690415] __fuse_simple_request+0xc49/0x1350 [fuse]
[10159.694677] ? wake_bit_function+0x210/0x210
[10159.697145] fuse_do_getattr+0x2cb/0x600 [fuse]



Aborting the connection(s) 'fixes' that, but looks like it triggers
another issue. Timeouts would certainly help, but it still should
work automatically.


Thanks,
Bernd