Messages in this thread | | | Date | Thu, 8 Mar 2018 16:23:12 +0800 | From | Herbert Xu <> | Subject | Re: [PATCH v2 net] net: xfrm: use preempt-safe this_cpu_read() in ipcomp_alloc_tfms() |
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On Wed, Mar 07, 2018 at 02:42:53PM -0800, Greg Hackmann wrote: > f7c83bcbfaf5 ("net: xfrm: use __this_cpu_read per-cpu helper") added a > __this_cpu_read() call inside ipcomp_alloc_tfms(). > > At the time, __this_cpu_read() required the caller to either not care > about races or to handle preemption/interrupt issues. 3.15 tightened > the rules around some per-cpu operations, and now __this_cpu_read() > should never be used in a preemptible context. On 3.15 and later, we > need to use this_cpu_read() instead. > > syzkaller reported this leading to the following kernel BUG while > fuzzing sendmsg:
Please explain why we can't revert f7c83bcbfaf5 instead.
Your patch contradicts the comment above the line that you're changing.
Thanks, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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