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Patch "kernel/ucount.c: mark user_header with kmemleak_ignore()" has been added to the 4.9-stable tree

PATCH [email protected] 1 participant 1 message Jun 15, 2017 Stable branch

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This is a note to let you know that I've just added the patch titled

kernel/ucount.c: mark user_header with kmemleak_ignore()

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kernel-ucount.c-mark-user_header-with-kmemleak_ignore.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Thu Jun 15 11:38:13 CEST 2017

From: "Luis R. Rodriguez" <[email protected]>
Date: Tue, 23 May 2017 21:53:47 -0400
Subject: kernel/ucount.c: mark user_header with kmemleak_ignore()

From: "Luis R. Rodriguez" <[email protected]>

[ Upstream commit ed5bd7dc88edf4a4a9c67130742b1b59aa017a5f ]

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:
     kmemleak_alloc+0x4a/0xa0
     __kmalloc+0x144/0x260
     __register_sysctl_table+0x54/0x5e0
     register_sysctl+0x1b/0x20
     user_namespace_sysctl_init+0x17/0x34
     do_one_initcall+0x52/0x1a0
     kernel_init_freeable+0x173/0x200
     kernel_init+0xe/0x100
     ret_from_fork+0x2c/0x40

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.

---
 kernel/ucount.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
kernel/ucount.c +1 -2
@@ -231,11 +231,10 @@ static __init int user_namespace_sysctl_
 	 * 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);
-
-

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/kernel-ucount.c-mark-user_header-with-kmemleak_ignore.patch