[PATCH 5.16 0939/1017] watch_queue: Free the page array when watch_queue is dismantled

Greg Kroah-Hartman
2022-04-05T13:48:33Z

From: Eric Dumazet <edumazet@google.com>

commit b490207017ba237d97b735b2aa66dc241ccd18f5 upstream.

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:
kmalloc_array include/linux/slab.h:621 [inline]
kcalloc include/linux/slab.h:652 [inline]
watch_queue_set_size+0x12f/0x2e0 kernel/watch_queue.c:251
pipe_ioctl+0x82/0x140 fs/pipe.c:632
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]

Reported-by: syzbot+25ea042ae28f3888727a@syzkaller.appspotmail.com
Fixes: c73be61cede5 ("pipe: Add general notification queue support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20220322004654.618274-1-eric.dumazet@gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/watch_queue.c | 1 +
1 file changed, 1 insertion(+)

--- a/kernel/watch_queue.c
+++ b/kernel/watch_queue.c
@@ -373,6 +373,7 @@ static void __put_watch_queue(struct kre

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);