Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 28 Sep 2017 21:00:52 -0700 | Subject | Re: Kernel panic - not syncing: Fatal exception in interrupt (file_free_rcu+0x14) |
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On Thu, Sep 28, 2017 at 8:32 PM, Kyle Sanderson <kyle.leet@gmail.com> wrote: > Not sure if the stack is crap or not, but this looks like an RCU crash? > > https://i.imgur.com/sBnNe1p.jpg
Hmm. Not the clearest picture, and the "Code:" line in particular is missing the interesting part, but at a guess it's taking a fault in put_cred(), which inlines to
if (atomic_dec_and_test(&(cred)->usage)) __put_cred(cred);
and I think it's that "cred" pointer that may be NULL, which makes "&(cred)->usage" be a NULL pointer too, and you get a page fault when it tries to decrement the usage count.
Now, it goes without saying that the cred pointer should never *be* NULL on a filp that is on the RCU freeing list, because we always initialize file->f_cred when we allocate a file to the current creds.
So there's something odd going on. Possibly entirely unrelated memory corruption.
Nothing obvious stands out, I think we'd need to see more of a pattern of the problem to see what is up.
Linus
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