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From: David Howells <dhowells@redhat.com>
To: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: dhowells@redhat.com, christophe.jaillet@wanadoo.fr,
	linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] KASAN: null-ptr-deref Read in __free_pages
Date: Mon, 21 Mar 2022 09:37:57 +0000	[thread overview]
Message-ID: <985901.1647855477@warthog.procyon.org.uk> (raw)
In-Reply-To: <1745593.TLkxdtWsSY@leap>

Fabio M. De Francesco <fmdefrancesco@gmail.com> wrote:

> I cannot have any objection, it's up to you to decide :)

Of course you can object.  That's kind of the point of a review;-)

How about the attached instead, then?

David
---
--- a/kernel/watch_queue.c
+++ b/kernel/watch_queue.c
@@ -271,9 +271,8 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes)
 	return 0;
 
 error_p:
-	for (i = 0; i < nr_pages; i++)
-		if (pages[i])
-			__free_page(pages[i]);
+	while (--i >= 0)
+		__free_page(pages[i]);
 	kfree(pages);
 error:
 	(void) account_pipe_buffers(pipe->user, nr_pages, pipe->nr_accounted);


  reply	other threads:[~2022-03-21  9:38 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-20 22:04 [syzbot] KASAN: null-ptr-deref Read in __free_pages syzbot
2022-03-20 23:32 ` Fabio M. De Francesco
2022-03-20 23:38   ` syzbot
2022-03-20 23:40 ` Fabio M. De Francesco
2022-03-20 23:50   ` syzbot
2022-03-21  0:28 ` Fabio M. De Francesco
2022-03-21  0:37   ` syzbot
2022-03-21  8:46   ` David Howells
2022-03-21  9:02     ` Fabio M. De Francesco
2022-03-21  9:37       ` David Howells [this message]
2022-03-21  8:24 ` David Howells
2022-03-21  8:34   ` syzbot
2022-03-21  8:43   ` Fabio M. De Francesco
2022-03-21  8:50   ` Fabio M. De Francesco
2022-03-21 11:19 ` David Howells
2022-03-21 11:30   ` syzbot

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