Messages in this thread | | | Subject | Re: dm: Use kzalloc for all structs with embedded biosets/mempools | From | Jens Axboe <> | Date | Tue, 5 Jun 2018 08:48:42 -0600 |
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On 6/5/18 8:45 AM, Mike Snitzer wrote: > On Tue, Jun 05 2018 at 10:22P -0400, > Jens Axboe <axboe@kernel.dk> wrote: > >> On 6/5/18 3:26 AM, Kent Overstreet wrote: >>> mempool_init()/bioset_init() require that the mempools/biosets be zeroed >>> first; they probably should not _require_ this, but not allocating those >>> structs with kzalloc is a fairly nonsensical thing to do (calling >>> mempool_exit()/bioset_exit() on an uninitialized mempool/bioset is legal >>> and safe, but only works if said memory was zeroed.) >>> >>> Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> >>> --- >>> >>> Linus, >>> >>> I fucked up majorly on the bioset/mempool conversion - I forgot to check that >>> everything biosets/mempools were being embedded in was actually being zeroed on >>> allocation. Device mapper currently explodes, you'll probably want to apply this >>> patch post haste. >>> >>> I have now done that auditing, for every single conversion - this patch fixes >>> everything I found. There do not seem to be any incorrect ones outside of device >>> mapper... >>> >>> We'll probably want a second patch that either a) changes >>> bioset_init()/mempool_init() to zero the passed in bioset/mempool first, or b) >>> my preference, WARN() or BUG() if they're passed memory that isn't zeroed. >> >> Odd, haven't seen a crash, but probably requires kasan or poisoning to >> trigger anything? Mike's tree also had the changes, since they were based >> on the block tree. >> >> I can queue this up and ship it later today. Mike, you want to review >> this one? > > Yes, looks good. > > From the start of revisiting these changes last week, Kent and I > discussed whether it was safe to call mempool_exit() even if > mempool_init() failed or was never called. He advised that it was so > long as the containing structure was zeroed. But I forgot to audit that > aspect. So this was an oversight by both of us. > > DM core uses kvzalloc_node for struct mapped_device and cache, crypt, > integrity, verity-fec and zoned targets are already using kzalloc as > needed. > > Acked-by: Mike Snitzer <snitzer@redhat.com>
Thanks Mike, I'll push this out this morning.
-- Jens Axboe
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