[PATCH] ucount: mark user_header with kmemleak_ignore()

From: Luis R. Rodriguez
Date: Fri Feb 03 2017 - 16:14:13 EST


The user_header gets caught by kmemleak with the following splat
as missing a free:

unreferenced object 0xffff99667a733d80 (size 96):
comm "swapper/0", pid 1, jiffies 4294892317 (age 62191.468s)
hex dump (first 32 bytes):
a0 b6 92 b4 ff ff ff ff 00 00 00 00 01 00 00 00 ................
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffffb3a5f7ea>] kmemleak_alloc+0x4a/0xa0
[<ffffffffb36050d4>] __kmalloc+0x144/0x260
[<ffffffffb36a7144>] __register_sysctl_table+0x54/0x5e0
[<ffffffffb36a76eb>] register_sysctl+0x1b/0x20
[<ffffffffb416fe17>] user_namespace_sysctl_init+0x17/0x34
[<ffffffffb3402192>] do_one_initcall+0x52/0x1a0
[<ffffffffb414d1bd>] kernel_init_freeable+0x173/0x200
[<ffffffffb3a5c23e>] kernel_init+0xe/0x100
[<ffffffffb3a6b57c>] ret_from_fork+0x2c/0x40
[<ffffffffffffffff>] 0xffffffffffffffff

The BUG_ON()s are intended to crash so no need to clean up after
ourselves on error there. This is also a kernel/ subsys_init() we
don't need a respective exit call here as this is never modular,
so just white list it.

Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
---
kernel/ucount.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/ucount.c b/kernel/ucount.c
index 68716403b261..8a11fc0cb459 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -231,11 +231,10 @@ static __init int user_namespace_sysctl_init(void)
* properly.
*/
user_header = register_sysctl("user", empty);
+ kmemleak_ignore(user_header);
BUG_ON(!user_header);
BUG_ON(!setup_userns_sysctls(&init_user_ns));
#endif
return 0;
}
subsys_initcall(user_namespace_sysctl_init);
-
-
--
2.11.0