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

From: Alexei Starovoitov
Date: Sat Nov 17 2018 - 00:20:18 EST


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 <naresh.kamboju@xxxxxxxxxx>
> Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
> Signed-off-by: Roman Gushchin <guro@xxxxxx>
> Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>

applied to bpf tree, thanks