[v1] watch_queue: Free the page array when watch_queue is dismantled

[PATCH] watch_queue: Free the page array when watch_queue is dismantled

Posted by Eric Dumazet 4 years, 3 months ago

From: Eric Dumazet <edumazet@google.com>

Commit 7ea1a0124b6d ("watch_queue: Free the alloc bitmap
when the watch_queue is torn down") took care of the bitmap,
but not the page array.

BUG: memory leak
unreferenced object 0xffff88810d9bc140 (size 32):
  comm "syz-executor335", pid 3603, jiffies 4294946994 (age 12.840s)
  hex dump (first 32 bytes):
    40 a7 40 04 00 ea ff ff 00 00 00 00 00 00 00 00  @.@.............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff81459bff>] kmalloc_array include/linux/slab.h:621 [inline]
    [<ffffffff81459bff>] kcalloc include/linux/slab.h:652 [inline]
    [<ffffffff81459bff>] watch_queue_set_size+0x12f/0x2e0 kernel/watch_queue.c:251
    [<ffffffff8159fcf2>] pipe_ioctl+0x82/0x140 fs/pipe.c:632
    [<ffffffff815b601c>] vfs_ioctl fs/ioctl.c:51 [inline]
    [<ffffffff815b601c>] __do_sys_ioctl fs/ioctl.c:874 [inline]
    [<ffffffff815b601c>] __se_sys_ioctl fs/ioctl.c:860 [inline]
    [<ffffffff815b601c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:860
    [<ffffffff84493a05>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff84493a05>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84600068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: c73be61cede5 ("pipe: Add general notification queue support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jann Horn <jannh@google.com>
---
 kernel/watch_queue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c
index 00703444a21948deaa8b7ac8b57b73528badff0d..58fe68664eb1b0001cb00c8d046e108462df4836 100644
--- a/kernel/watch_queue.c
+++ b/kernel/watch_queue.c
@@ -370,6 +370,7 @@ static void __put_watch_queue(struct kref *kref)
 
 	for (i = 0; i < wqueue->nr_pages; i++)
 		__free_page(wqueue->notes[i]);
+	kfree(wqueue->notes);
 	bitmap_free(wqueue->notes_bitmap);
 
 	wfilter = rcu_access_pointer(wqueue->filter);
-- 
2.35.1.894.gb6a874cedc-goog

Re: [PATCH] watch_queue: Free the page array when watch_queue is dismantled

Posted by Eric Dumazet 4 years, 2 months ago

ping ?

On Mon, Mar 21, 2022 at 5:47 PM Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
> From: Eric Dumazet <edumazet@google.com>
>
> Commit 7ea1a0124b6d ("watch_queue: Free the alloc bitmap
> when the watch_queue is torn down") took care of the bitmap,
> but not the page array.
>
> BUG: memory leak
> unreferenced object 0xffff88810d9bc140 (size 32):
>   comm "syz-executor335", pid 3603, jiffies 4294946994 (age 12.840s)
>   hex dump (first 32 bytes):
>     40 a7 40 04 00 ea ff ff 00 00 00 00 00 00 00 00  @.@.............
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff81459bff>] kmalloc_array include/linux/slab.h:621 [inline]
>     [<ffffffff81459bff>] kcalloc include/linux/slab.h:652 [inline]
>     [<ffffffff81459bff>] watch_queue_set_size+0x12f/0x2e0 kernel/watch_queue.c:251
>     [<ffffffff8159fcf2>] pipe_ioctl+0x82/0x140 fs/pipe.c:632
>     [<ffffffff815b601c>] vfs_ioctl fs/ioctl.c:51 [inline]
>     [<ffffffff815b601c>] __do_sys_ioctl fs/ioctl.c:874 [inline]
>     [<ffffffff815b601c>] __se_sys_ioctl fs/ioctl.c:860 [inline]
>     [<ffffffff815b601c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:860
>     [<ffffffff84493a05>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>     [<ffffffff84493a05>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>     [<ffffffff84600068>] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Fixes: c73be61cede5 ("pipe: Add general notification queue support")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: David Howells <dhowells@redhat.com>
> Cc: Jann Horn <jannh@google.com>
> ---
>  kernel/watch_queue.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c
> index 00703444a21948deaa8b7ac8b57b73528badff0d..58fe68664eb1b0001cb00c8d046e108462df4836 100644
> --- a/kernel/watch_queue.c
> +++ b/kernel/watch_queue.c
> @@ -370,6 +370,7 @@ static void __put_watch_queue(struct kref *kref)
>
>         for (i = 0; i < wqueue->nr_pages; i++)
>                 __free_page(wqueue->notes[i]);
> +       kfree(wqueue->notes);
>         bitmap_free(wqueue->notes_bitmap);
>
>         wfilter = rcu_access_pointer(wqueue->filter);
> --
> 2.35.1.894.gb6a874cedc-goog
>

Re: [PATCH] watch_queue: Free the page array when watch_queue is dismantled

Posted by David Howells 4 years, 2 months ago

Eric Dumazet <eric.dumazet@gmail.com> wrote:

> Reported-by: syzbot <syzkaller@googlegroups.com>

Should this be the following?

	Reported-by: syzbot+25ea042ae28f3888727a@syzkaller.appspotmail.com

David

Re: [PATCH] watch_queue: Free the page array when watch_queue is dismantled

Posted by Eric Dumazet 4 years, 2 months ago

On Mon, Mar 28, 2022 at 3:34 AM David Howells <dhowells@redhat.com> wrote:
>
> Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
> > Reported-by: syzbot <syzkaller@googlegroups.com>
>
> Should this be the following?
>
>         Reported-by: syzbot+25ea042ae28f3888727a@syzkaller.appspotmail.com
>

This can be.

I mostly send fixes while the syzbot report is not public, so I used a
generic form.
(Because I also take care of feeding the bot with the needed "#syz
fix:  patch_title")

In this case, I have released the syzbot report, because I saw you had
a patch for this issue already.

Please add "Reported-by:
syzbot+25ea042ae28f3888727a@syzkaller.appspotmail.com" when you submit
your fix, thanks !