From: Matthew Wilcox <willy@infradead.org>
To: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: viro@zeniv.linux.org.uk, dhowells@redhat.com,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3] fs: fix undefined behavior in bit shift for SB_NOUSER
Date: Mon, 31 Oct 2022 14:28:08 +0000 [thread overview]
Message-ID: <Y1/beLrf1gr3/b2u@casper.infradead.org> (raw)
In-Reply-To: <20221031142621.194389-1-cuigaosheng1@huawei.com>
On Mon, Oct 31, 2022 at 10:26:21PM +0800, Gaosheng Cui wrote:
> Shifting signed 32-bit value by 31 bits is undefined, so changing most
> significant bit to unsigned, and mark all of the flags as unsigned so
> that we don't mix types. The UBSAN warning calltrace like below:
>
> UBSAN: shift-out-of-bounds in fs/namespace.c:2330:33
> left shift of 1 by 31 places cannot be represented in type 'int'
> Call Trace:
> <TASK>
> dump_stack_lvl+0x7d/0xa5
> dump_stack+0x15/0x1b
> ubsan_epilogue+0xe/0x4e
> __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
> graft_tree+0x36/0xf0
> do_add_mount+0x98/0x100
> path_mount+0xbd6/0xd50
> init_mount+0x6a/0xa3
> devtmpfs_setup+0x47/0x7e
> devtmpfsd+0x1a/0x50
> kthread+0x126/0x160
> ret_from_fork+0x1f/0x30
> </TASK>
>
> Fixes: e462ec50cb5f ("VFS: Differentiate mount flags (MS_*) from internal superblock flags")
> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
next prev parent reply other threads:[~2022-10-31 14:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-31 14:26 [PATCH v3] fs: fix undefined behavior in bit shift for SB_NOUSER Gaosheng Cui
2022-10-31 14:28 ` Matthew Wilcox [this message]
2022-11-19 5:14 ` Al Viro
-- strict thread matches above, loose matches on Subject: below --
2023-04-24 5:01 [PATCH V2] " Al Viro
2023-04-24 5:18 ` [PATCH V3] " Hao Ge
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y1/beLrf1gr3/b2u@casper.infradead.org \
--to=willy@infradead.org \
--cc=cuigaosheng1@huawei.com \
--cc=dhowells@redhat.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.