Messages in this thread | | | Date | Tue, 13 Jul 2021 22:54:47 +0100 | From | Mel Gorman <> | Subject | Re: [mm/vmalloc] 5c1f4e690e: BUG:sleeping_function_called_from_invalid_context_at_mm/page_alloc.c |
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On Tue, Jul 13, 2021 at 11:19:29AM -0700, Linus Torvalds wrote: > On Tue, Jul 13, 2021 at 7:06 AM kernel test robot <oliver.sang@intel.com> wrote: > > > > [ 131.014885] BUG: sleeping function called from invalid context at mm/page_alloc.c:4992 > > Strange. The call chain doesn't actually seem to be anything off: it's > writev -> sock_write_iter -> sock_sendmsg -> netlink_sendmsg -> > vmalloc. > > All good to sleep as far as I can tell. The warning itself seems to be just > > might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM); > > in prepare_alloc_pages(). > > I don't see what's wrong with that commit, but it does seem to be very > consistent, in that the parent doesn't have it: >
It's almost certainly going to be fixed by https://lore.kernel.org/r/20210713152100.10381-2-mgorman@techsingularity.net whenever it hits your tree as part of this series https://lore.kernel.org/lkml/20210713152100.10381-1-mgorman@techsingularity.net/. It should make its way through Andrew's tree before RC2 but if he is busy I'll create a git pull request.
> which means that the might_sleep_if() happens _after_ > __alloc_pages_bulk() has disabled interrupts. That would explain it, > but the stack_depot_save() thing actually makes that call chain really > hard to read because it duplicates the addresses on the stack. > > I don't see the nesting there, but that's what it kind of smells like to me. > > Anybody? >
The problem is that PAGE_OWNER can recurse allocate from bulk allocation context to store the caller stack. When I wrote the patch, I missed that prep_new_page can allocate if PAGE_OWNER is active. The most relevant part of the trace is
[ 131.092667] stack_depot_save+0x390/0x4c0
-- Mel Gorman SUSE Labs
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