linux-kernel - [patch] fs: fix __block_write_full_page error case buffer submission

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>] [day] [month] [year] [list]

Message-ID: <20070206083327.GC16965@wotan.suse.de>
Date:	Tue, 6 Feb 2007 09:33:27 +0100
From:	Nick Piggin <npiggin@...e.de>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [patch] fs: fix __block_write_full_page error case buffer submission

OK, I had initially been going to send a patch to bring the common case
into line with the error case to reduce the chance of rare bugs, but
that's stupid because the common case is obviously the better tested one!

Oh, and the error case seems to have a bug as well.

--
Andrew noticed that unlocking the page before submitting all buffers for
writeout could cause problems if the IO completes before we've finished
messing around with the page buffers, and they subsequently get freed.

Even if there were no bug, it is a good idea to bring the error case
into line with the common case here.

Signed-off-by: Nick Piggin <npiggin@...e.de>

Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c
+++ linux-2.6/fs/buffer.c
@@ -1732,7 +1732,6 @@ recover:
 	SetPageError(page);
 	BUG_ON(PageWriteback(page));
 	set_page_writeback(page);
-	unlock_page(page);
 	do {
 		struct buffer_head *next = bh->b_this_page;
 		if (buffer_async_write(bh)) {
@@ -1742,6 +1741,7 @@ recover:
 		}
 		bh = next;
 	} while (bh != head);
+	unlock_page(page);
 	goto done;
 }
 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/