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openzfs / spl

A shim layer which adds the core interfaces required for OpenZFS.
https://zfsonlinux.org/
GNU General Public License v2.0
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Remove misguided HAVE_MUTEX_OWNER check, take 2 #639

Closed verygreen closed 7 years ago

verygreen commented 7 years ago

It is just plain unsafe to peek inside in-kernel mutex structure and make assumptions about what kernel does with those internal fields like owner.

Kernel is all too happy to stop doing the expected things like tracing lock owner once you load a tainted module like spl/zfs that is not GPL.

As such you will get instant assertion failures like this:

VERIFY3((((volatile typeof((&((&zo->zo_lock)->m_mutex))->owner) )& ((&((&zo->zo_lock)->m_mutex))->owner))) == ((void *)0)) failed (ffff88030be28500 == (null)) PANIC at zfs_onexit.c:104:zfs_onexit_destroy() Showing stack for process 3626 CPU: 0 PID: 3626 Comm: mkfs.lustre Tainted: P OE ------------ 3.10.0-debug #1 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 Call Trace: dump_stack+0x19/0x1b spl_dumpstack+0x44/0x50 [spl] spl_panic+0xbf/0xf0 [spl] zfs_onexit_destroy+0x17c/0x280 [zfs] zfsdev_release+0x48/0xd0 [zfs]

Signed-off-by: Oleg Drokin green@linuxhacker.ru Closes #632

behlendorf commented 7 years ago

Test results look good. Merged.