linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jia-Ju Bai <baijiaju1990@163.com>
To: viro@zeniv.linux.org.uk, jack@suse.com, sagi@grimberg.me,
	james.smart@broadcom.com
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, Jia-Ju Bai <baijiaju1990@163.com>
Subject: [PATCH] ext2/super: Fix a possible sleep-in-atomic bug in parse_options
Date: Sat,  7 Oct 2017 09:20:46 +0800	[thread overview]
Message-ID: <1507339246-13067-1-git-send-email-baijiaju1990@163.com> (raw)

The kernel may sleep under a spinlock, and the function call path is:
ext2_remount
  parse_options
    match_int
      match_number (lib/parser.c)
        kmalloc(GFP_KERNEL) --> may sleep

To fix it, GFP_KERNEL is replaced with GFP_ATOMIC.
This bug is found by my static analysis tool and my code review.

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
---
 lib/parser.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/parser.c b/lib/parser.c
index 3278958..bc6e2ce 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -133,7 +133,7 @@ static int match_number(substring_t *s, int *result, int base)
 	long val;
 	size_t len = s->to - s->from;
 
-	buf = kmalloc(len + 1, GFP_KERNEL);
+	buf = kmalloc(len + 1, GFP_ATOMIC);
 	if (!buf)
 		return -ENOMEM;
 	memcpy(buf, s->from, len);
-- 
1.7.9.5

             reply	other threads:[~2017-10-07  1:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-07  1:20 Jia-Ju Bai [this message]
2017-10-07  1:37 ` [PATCH] ext2/super: Fix a possible sleep-in-atomic bug in parse_options Linus Torvalds
2017-10-07  1:55   ` Jia-Ju Bai
2017-10-07  2:02   ` Al Viro
2017-10-07  2:28     ` Al Viro
2017-10-09 13:32     ` Jan Kara
2017-10-08 22:20 ` Dave Chinner

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=1507339246-13067-1-git-send-email-baijiaju1990@163.com \
    --to=baijiaju1990@163.com \
    --cc=jack@suse.com \
    --cc=james.smart@broadcom.com \
    --cc=linux-ext4@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sagi@grimberg.me \
    --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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).