linux-kernel - Re: [BUG] fs/f2fs: a possible sleep-in-atomic bug in f2fs_trace

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Tue, 12 Dec 2017 10:00:54 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Jia-Ju Bai <baijiaju1990@...il.com>, <jaegeuk@...nel.org>
CC:     <linux-f2fs-devel@...ts.sourceforge.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] fs/f2fs: a possible sleep-in-atomic bug in f2fs_trace_pid

Hi Jia-Ju,

Thanks for your report. :)

On 2017/12/12 8:59, Jia-Ju Bai wrote:
> According to fs/f2fs/trace.c, the kernel module may sleep under a spinlock.
> The function call path is:
> f2fs_trace_pid (acquire the spinlock)
>    f2fs_radix_tree_insert
>      cond_resched --> may sleep
> 
> I do not find a good way to fix it, so I only report.
> This possible bug is found by my static analysis tool (DSAC) and my code 
> review.
That's a known issue, and there are other problems in IO trace related codes,
so I want to refactor the code directly, you could check the code in below link:

https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git/commit/?h=f2fs-dev&id=d895154be1733e2bd29c9e64b57e4e201f0e8a0c

But the patch still needs debugging so far. Since the IO trace feature is off
by default, I expect the impaction is limited, so I pend the debug job on this
patch.

Anyway, I think this issue you reported should be fixed first, let me make the
fixing part independent from original patch for fixing.

Thanks,

> 
> 
> Thanks,
> Jia-Ju Bai
> 
>