From: Martin Sperl <kernel@martin.sperl.org>
Date: Sun, 10 May 2015 07:50:45 +0000 (+0000)
Subject: spi: fix race freeing dummy_tx/rx before it is unmapped
X-Git-Tag: omap-for-v4.3/legacy-v2-signed~175^2~7^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8e76ef88f607174082023f50b87fe12dcdbe5db5;p=pandora-kernel.git

spi: fix race freeing dummy_tx/rx before it is unmapped

Fix a race (with some kernel configurations) where a queued
master->pump_messages runs and frees dummy_tx/rx before
spi_unmap_msg is running (or is finished).

This results in the following messages:
  BUG: Bad page state in process
  page:db7ba030 count:0 mapcount:0 mapping:  (null) index:0x0
  flags: 0x200(arch_1)
  page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
  ...

Reported-by: Noralf Trønnes <noralf@tronnes.org>
Suggested-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
---

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