Re: [PATCH 6/6 linux-next] ext4: fix memory leak in ext4_insert_range()

From: Theodore Ts'o
Date: Thu Sep 15 2016 - 11:41:19 EST


On Wed, Aug 24, 2016 at 10:03:20PM +0200, Fabian Frederick wrote:
> Running xfstests generic/013 with kmemleak gives the following:
>
> unreferenced object 0xffff8801d3d27de0 (size 96):
> comm "fsstress", pid 4941, jiffies 4294860168 (age 53.485s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff818eaaf3>] kmemleak_alloc+0x23/0x40
> [<ffffffff81179805>] __kmalloc+0xf5/0x1d0
> [<ffffffff8122ef5c>] ext4_find_extent+0x1ec/0x2f0
> [<ffffffff8123530c>] ext4_insert_range+0x34c/0x4a0
> [<ffffffff81235942>] ext4_fallocate+0x4e2/0x8b0
> [<ffffffff81181334>] vfs_fallocate+0x134/0x210
> [<ffffffff8118203f>] SyS_fallocate+0x3f/0x60
> [<ffffffff818efa9b>] entry_SYSCALL_64_fastpath+0x13/0x8f
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> Problem seems mitigated by dropping refs and freeing path
> when there's no path[depth].p_ext
>
> Signed-off-by: Fabian Frederick <fabf@xxxxxxxxx>

Applied, thanks.

- Ted