Differential D14955

powerpc/ofw: Fix malloc inside lock
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Authored by breno.leitao_gmail.com on Apr 3 2018, 8:09 PM.

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Reviewers

jhibbits
nwhitehorn
mjg

Commits

rS332286: powerpc/ofw: Fix malloc inside lock

Summary

Currently ofw_real_bounce_alloc() is requesting memory, using WAITOK, holding a
non-sleepable locks, called 'OF Bounce Page'.

Since the request is inside the a lock, it should not sleep and return
immediately using the NOWAIT flag.

If you enable witness option, you see:

vmem_alloc with the following non-sleepable locks held:
exclusive sleep mutex OF Bounce Page (OF Bounce Page) r = 0 (0xc0000000016f0d28) locked @ /root/kernel/freebsd/sys/powerpc/ofw/ofw_real.c:212
stack backtrace:
#0 0xc0000000006a1db0 at ??+0
#1 0xc0000000006a4448 at ??+0
#2 0xc00000000069ee6c at ??+0
#3 0xc00000000094db00 at ??+0
#4 0xc00000000094de80 at ??+0
#5 0xc0000000005fbcb0 at ??+0
#6 0xc00000000099ae98 at ??+0
#7 0xc0000000005adf14 at ??+0
#8 0xc000000000102744 at ??+0
vmem_xalloc with the following non-sleepable locks held:
exclusive sleep mutex OF Bounce Page (OF Bounce Page) r = 0 (0xc0000000016f0d28) locked @ /root/kernel/freebsd/sys/powerpc/ofw/ofw_real.c:212
stack backtrace:
#0 0xc0000000006a1db0 at ??+0
#1 0xc0000000006a4448 at ??+0
#2 0xc00000000069e4a4 at ??+0
#3 0xc00000000069eef8 at ??+0
#4 0xc00000000094db00 at ??+0
#5 0xc00000000094de80 at ??+0
#6 0xc0000000005fbcb0 at ??+0
#7 0xc00000000099ae98 at ??+0
#8 0xc0000000005adf14 at ??+0
#9 0xc000000000102744 at ??+0

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Build Status

Buildable 15999
Build 15981: arc lint + arc unit

Event Timeline

breno.leitao_gmail.com created this revision.Apr 3 2018, 8:09 PM

Herald added a subscriber: jhibbits. · View Herald TranscriptApr 3 2018, 8:09 PM

Harbormaster completed remote builds in B15963: Diff 41048.Apr 3 2018, 8:09 PM

breno.leitao_gmail.com added reviewers: jhibbits, nwhitehorn.Apr 3 2018, 8:36 PM

This looks odd. of_bounc_mtx is initialized MTX_DEF, which is a sleepable mutex. Are there other locking changes made that make this not the case?

nwhitehorn accepted this revision.Apr 5 2018, 8:50 PM

This revision is now accepted and ready to land.Apr 5 2018, 8:50 PM

Updating the patch to remove the mem alloc from outside the lock section.

This revision now requires review to proceed.Apr 5 2018, 9:00 PM

Harbormaster completed remote builds in B15999: Diff 41152.Apr 5 2018, 9:00 PM

jhibbits accepted this revision.Apr 5 2018, 9:01 PM

This revision is now accepted and ready to land.Apr 5 2018, 9:01 PM

mjg requested changes to this revision.Apr 5 2018, 10:33 PM

mjg added a subscriber: mjg.

mjg added inline comments.

sys/powerpc/ofw/ofw_real.c
217	this does not indicate who tried to allocate it. at the very least this should also contain func
223	i don't see any added value of this comment

This revision now requires changes to proceed.Apr 5 2018, 10:33 PM

Updating the patch with mjg's suggestions. Thanks for the review.

Harbormaster completed remote builds in B16021: Diff 41194.Apr 6 2018, 5:51 PM

mjg accepted this revision.Apr 6 2018, 5:55 PM

This revision is now accepted and ready to land.Apr 6 2018, 5:55 PM

Closed by commit rS332286: powerpc/ofw: Fix malloc inside lock (authored by jhibbits). · Explain WhyApr 8 2018, 4:44 PM

This revision was automatically updated to reflect the committed changes.

Herald added a subscriber: imp. · View Herald TranscriptApr 8 2018, 4:44 PM

Revision Contents
Changeset List

Path

Size

sys/

powerpc/

ofw/

14 lines

Diff 41152

sys/powerpc/ofw/ofw_real.c

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