2018-11-14 18:01:52

by Roman Gushchin

[permalink] [raw]
Subject: [PATCH bpf] bpf: allocate local storage buffers using GFP_ATOMIC

Naresh reported an issue with the non-atomic memory allocation of
cgroup local storage buffers:

[ 73.047526] BUG: sleeping function called from invalid context at
/srv/oe/build/tmp-rpb-glibc/work-shared/intel-corei7-64/kernel-source/mm/slab.h:421
[ 73.060915] in_atomic(): 1, irqs_disabled(): 0, pid: 3157, name: test_cgroup_sto
[ 73.068342] INFO: lockdep is turned off.
[ 73.072293] CPU: 2 PID: 3157 Comm: test_cgroup_sto Not tainted
4.20.0-rc2-next-20181113 #1
[ 73.080548] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[ 73.088018] Call Trace:
[ 73.090463] dump_stack+0x70/0xa5
[ 73.093783] ___might_sleep+0x152/0x240
[ 73.097619] __might_sleep+0x4a/0x80
[ 73.101191] __kmalloc_node+0x1cf/0x2f0
[ 73.105031] ? cgroup_storage_update_elem+0x46/0x90
[ 73.109909] cgroup_storage_update_elem+0x46/0x90

cgroup_storage_update_elem() (as well as other update map update
callbacks) is called with disabled preemption, so GFP_ATOMIC
allocation should be used: e.g. alloc_htab_elem() in hashtab.c.

Reported-by: Naresh Kamboju <[email protected]>
Tested-by: Naresh Kamboju <[email protected]>
Signed-off-by: Roman Gushchin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
---
kernel/bpf/local_storage.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index c97a8f968638..bed9d48a7ae9 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -139,7 +139,8 @@ static int cgroup_storage_update_elem(struct bpf_map *map, void *_key,
return -ENOENT;

new = kmalloc_node(sizeof(struct bpf_storage_buffer) +
- map->value_size, __GFP_ZERO | GFP_USER,
+ map->value_size,
+ __GFP_ZERO | GFP_ATOMIC | __GFP_NOWARN,
map->numa_node);
if (!new)
return -ENOMEM;
--
2.17.2



2018-11-16 23:45:16

by Y Song

[permalink] [raw]
Subject: Re: [PATCH bpf] bpf: allocate local storage buffers using GFP_ATOMIC

On Wed, Nov 14, 2018 at 6:01 PM Roman Gushchin <[email protected]> wrote:
>
> Naresh reported an issue with the non-atomic memory allocation of
> cgroup local storage buffers:
>
> [ 73.047526] BUG: sleeping function called from invalid context at
> /srv/oe/build/tmp-rpb-glibc/work-shared/intel-corei7-64/kernel-source/mm/slab.h:421
> [ 73.060915] in_atomic(): 1, irqs_disabled(): 0, pid: 3157, name: test_cgroup_sto
> [ 73.068342] INFO: lockdep is turned off.
> [ 73.072293] CPU: 2 PID: 3157 Comm: test_cgroup_sto Not tainted
> 4.20.0-rc2-next-20181113 #1
> [ 73.080548] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
> 2.0b 07/27/2017
> [ 73.088018] Call Trace:
> [ 73.090463] dump_stack+0x70/0xa5
> [ 73.093783] ___might_sleep+0x152/0x240
> [ 73.097619] __might_sleep+0x4a/0x80
> [ 73.101191] __kmalloc_node+0x1cf/0x2f0
> [ 73.105031] ? cgroup_storage_update_elem+0x46/0x90
> [ 73.109909] cgroup_storage_update_elem+0x46/0x90
>
> cgroup_storage_update_elem() (as well as other update map update
> callbacks) is called with disabled preemption, so GFP_ATOMIC
> allocation should be used: e.g. alloc_htab_elem() in hashtab.c.
>
> Reported-by: Naresh Kamboju <[email protected]>
> Tested-by: Naresh Kamboju <[email protected]>
> Signed-off-by: Roman Gushchin <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
> Cc: Daniel Borkmann <[email protected]>

Acked-by: Yonghong Song <[email protected]>

> ---
> kernel/bpf/local_storage.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

2018-11-17 05:21:07

by Alexei Starovoitov

[permalink] [raw]
Subject: Re: [PATCH bpf] bpf: allocate local storage buffers using GFP_ATOMIC

On Wed, Nov 14, 2018 at 10:00:34AM -0800, Roman Gushchin wrote:
> Naresh reported an issue with the non-atomic memory allocation of
> cgroup local storage buffers:
>
> [ 73.047526] BUG: sleeping function called from invalid context at
> /srv/oe/build/tmp-rpb-glibc/work-shared/intel-corei7-64/kernel-source/mm/slab.h:421
> [ 73.060915] in_atomic(): 1, irqs_disabled(): 0, pid: 3157, name: test_cgroup_sto
> [ 73.068342] INFO: lockdep is turned off.
> [ 73.072293] CPU: 2 PID: 3157 Comm: test_cgroup_sto Not tainted
> 4.20.0-rc2-next-20181113 #1
> [ 73.080548] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
> 2.0b 07/27/2017
> [ 73.088018] Call Trace:
> [ 73.090463] dump_stack+0x70/0xa5
> [ 73.093783] ___might_sleep+0x152/0x240
> [ 73.097619] __might_sleep+0x4a/0x80
> [ 73.101191] __kmalloc_node+0x1cf/0x2f0
> [ 73.105031] ? cgroup_storage_update_elem+0x46/0x90
> [ 73.109909] cgroup_storage_update_elem+0x46/0x90
>
> cgroup_storage_update_elem() (as well as other update map update
> callbacks) is called with disabled preemption, so GFP_ATOMIC
> allocation should be used: e.g. alloc_htab_elem() in hashtab.c.
>
> Reported-by: Naresh Kamboju <[email protected]>
> Tested-by: Naresh Kamboju <[email protected]>
> Signed-off-by: Roman Gushchin <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
> Cc: Daniel Borkmann <[email protected]>

applied to bpf tree, thanks