On Thu 2020-05-28 11:05:17, Michal Hocko wrote:
> On Tue 26-05-20 11:10:54, Pavel Machek wrote:
> [...]
> > [38617.276517] oom_reaper: reaped process 31769 (chromium), now anon-rss:0kB, file-rss:0kB, shmem-rss:7968kB
> > [38617.277232] Xorg invoked oom-killer: gfp_mask=0x0(), order=0, oom_score_adj=0
> > [38617.277247] CPU: 0 PID: 2978 Comm: Xorg Not tainted 5.7.0-rc5-next-20200515+ #117
> > [38617.277256] Hardware name: LENOVO 17097HU/17097HU, BIOS 7BETD8WW (2.19 ) 03/31/2011
> > [38617.277266] Call Trace:
> > [38617.277286]  dump_stack+0x54/0x6e
> > [38617.277300]  dump_header+0x45/0x321
> > [38617.277313]  oom_kill_process.cold+0x9/0xe
> > [38617.277324]  ? out_of_memory+0x167/0x420
> > [38617.277336]  out_of_memory+0x1f2/0x420
> > [38617.277348]  pagefault_out_of_memory+0x34/0x56
> > [38617.277361]  mm_fault_error+0x4a/0x130
> > [38617.277372]  do_page_fault+0x3ce/0x416
> 
> The reason the OOM killer has been invoked is that the page fault
> handler has returned VM_FAULT_OOM. So this is not a result of the page
> allocator struggling to allocate a memory. It would be interesting to
> check which code path has returned this. 

Should the core WARN_ON if that happens and there's enough memory, or
something like that?

I grepped, and there are not too many users of VM_FAULT_OOM. These
might be relevant:

drivers/gpu/drm/ttm/ttm_bo_vm.c: *   VM_FAULT_OOM on out-of-memory
drivers/gpu/drm/ttm/ttm_bo_vm.c:			ret = VM_FAULT_OOM;
drivers/gpu/drm/ttm/ttm_bo_vm.c:				ret = VM_FAULT_OOM;
drivers/gpu/drm/i915/gem/i915_gem_mman.c:		return VM_FAULT_OOM;
drivers/gpu/drm/vkms/vkms_gem.c:				ret = VM_FAULT_OOM;
drivers/gpu/drm/vgem/vgem_drv.c:				ret = VM_FAULT_OOM;

Best regards,
									Pavel
-- 
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