The patch titled
Subject: memcg: css_alloc should return an ERR_PTR value on error
has been added to the -mm tree. Its filename is
memcg-css_alloc-should-return-an-err_ptr-value-on-error.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/memcg-css_alloc-should-return-an-err_ptr-value-on-error.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/memcg-css_alloc-should-return-an-err_ptr-value-on-error.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Tejun Heo <tj@xxxxxxxxxx>
Subject: memcg: css_alloc should return an ERR_PTR value on error
mem_cgroup_css_alloc() was returning NULL on failure while cgroup core
expected it to return an ERR_PTR value leading to the following NULL
deref after a css allocation failure. Fix it by return
ERR_PTR(-ENOMEM) instead. I'll also update cgroup core so that it
can handle NULL returns.
mkdir: page allocation failure: order:6, mode:0x240c0c0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO)
CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123
...
Call Trace:
[<ffffffff81321937>] dump_stack+0x68/0xa1
[<ffffffff811522f6>] warn_alloc_failed+0xd6/0x130
[<ffffffff81152816>] __alloc_pages_nodemask+0x4c6/0xf20
[<ffffffff8119df86>] alloc_pages_current+0x66/0xe0
[<ffffffff81153564>] alloc_kmem_pages+0x14/0x80
[<ffffffff811705ca>] kmalloc_order_trace+0x2a/0x1a0
[<ffffffff811a7a61>] __kmalloc+0x291/0x310
[<ffffffff811718dc>] memcg_update_all_caches+0x6c/0x130
[<ffffffff818d0290>] mem_cgroup_css_alloc+0x590/0x610
[<ffffffff810f4c7b>] cgroup_apply_control_enable+0x18b/0x370
[<ffffffff810f8afe>] cgroup_mkdir+0x1de/0x2e0
[<ffffffff8123cf35>] kernfs_iop_mkdir+0x55/0x80
[<ffffffff811c6599>] vfs_mkdir+0xb9/0x150
[<ffffffff811cc666>] SyS_mkdir+0x66/0xd0
[<ffffffff81002df3>] do_syscall_64+0x53/0x120
[<ffffffff818d719a>] entry_SYSCALL64_slow_path+0x25/0x25
...
BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0
IP: [<ffffffff810f2ca7>] init_and_link_css+0x37/0x220
PGD 34b1e067 PUD 3a109067 PMD 0
Oops: 0002 [#1] SMP
Modules linked in:
CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.2-20160422_131301-anatol 04/01/2014
task: ffff88007cbc5200 ti: ffff8800666d4000 task.ti: ffff8800666d4000
RIP: 0010:[<ffffffff810f2ca7>] [<ffffffff810f2ca7>] init_and_link_css+0x37/0x220
RSP: 0018:ffff8800666d7d90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffffffff810f2499 RSI: 0000000000000000 RDI: 0000000000000008
RBP: ffff8800666d7db8 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88005a5fb400
R13: ffffffff81f0f8a0 R14: ffff88005a5fb400 R15: 0000000000000010
FS: 00007fc944689700(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3aed0d2b80 CR3: 000000003a1e8000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
ffffffff81f0f8a0 ffffffff81f0f8a0 ffff88005a5fb400 0000000000000000
ffff88005a5fb400 ffff8800666d7e18 ffffffff810f4c9c ffff88005a5fb400
ffffffff82d23470 ffff88007cbc57f0 ffff88007cbc5200 ffff88007d013000
Call Trace:
[<ffffffff810f4c9c>] cgroup_apply_control_enable+0x1ac/0x370
[<ffffffff810f8afe>] cgroup_mkdir+0x1de/0x2e0
[<ffffffff8123cf35>] kernfs_iop_mkdir+0x55/0x80
[<ffffffff811c6599>] vfs_mkdir+0xb9/0x150
[<ffffffff811cc666>] SyS_mkdir+0x66/0xd0
[<ffffffff81002df3>] do_syscall_64+0x53/0x120
[<ffffffff818d719a>] entry_SYSCALL64_slow_path+0x25/0x25
Code: 89 f5 48 89 fb 49 89 d4 48 83 ec 08 8b 05 72 3b d8 00 85 c0 0f 85 60 01 00 00 4c 89 e7 e8 72 f7 ff ff 48 8d 7b 08 48 89 d9 31 c0 <48> c7 83 d0 00 00 00 00 00 00 00 48 83 e7 f8 48 29 f9 81 c1 d8
RIP [<ffffffff810f2ca7>] init_and_link_css+0x37/0x220
RSP <ffff8800666d7d90>
CR2: 00000000000000d0
---[ end trace a2d8836ae1e852d1 ]---
Link: http://lkml.kernel.org/r/20160621165740.GJ3262@xxxxxxxxxxxxxxx
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/memcontrol.c~memcg-css_alloc-should-return-an-err_ptr-value-on-error mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-css_alloc-should-return-an-err_ptr-value-on-error
+++ a/mm/memcontrol.c
@@ -4203,7 +4203,7 @@ mem_cgroup_css_alloc(struct cgroup_subsy
return &memcg->css;
fail:
mem_cgroup_free(memcg);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
static int
_
Patches currently in -mm which might be from tj@xxxxxxxxxx are
memcg-mem_cgroup_migrate-may-be-called-with-irq-disabled.patch
memcg-css_alloc-should-return-an-err_ptr-value-on-error.patch
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