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iwlwifi: fix double free/complete in firmware loading

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Linus reported that due to mac80211 failing to register
the device (due to WoWLAN) his machine crashed etc. as
we double-freed the vmalloc() firmware area. His patch
to fix it was very similar to this one but I noticed
that there's another bug in the area: we complete the
completion before starting, so since we're running in
a work struct context stop() could be called while in
the middle of start() which will almost certainly lead
to issues.

Make a modification similar to his to avoid the double-
free but also move the completion to another spot so it
is only done after start() either finished or failed so
that stop() can have a consistent state.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg 2012-06-05 19:56:06 +02:00 committed by John W. Linville
parent fcb6ff5e2c
commit f69a23b795
1 changed files with 7 additions and 2 deletions
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9
drivers/net/wireless/iwlwifi/iwl-drv.c
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@ -861,13 +861,18 @@ static void iwl_ucode_callback(const struct firmware *ucode_raw, void *context)
/* We have our copies now, allow OS release its copies */
release_firmware(ucode_raw);
complete(&drv->request_firmware_complete);
drv->op_mode = iwl_dvm_ops.start(drv->trans, drv->cfg, &drv->fw);
if (!drv->op_mode)
goto out_free_fw;
goto out_unbind;
/*
* Complete the firmware request last so that
* a driver unbind (stop) doesn't run while we
* are doing the start() above.
*/
complete(&drv->request_firmware_complete);
return;
try_again: