diff options
| author | Ming Lei <ming.lei@canonical.com> | 2012-08-04 08:01:17 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-17 00:13:18 +0400 |
| commit | 28eefa750b5e16b13bb869c2c4f7d624a43eb48b (patch) | |
| tree | 1bf6575f9884bdb49f9b8340d159b5ced97383e2 /drivers/base/firmware_class.c | |
| parent | 65710cb6ea315b3ef76a8a3da7be99afcf58d2bb (diff) | |
| download | linux-28eefa750b5e16b13bb869c2c4f7d624a43eb48b.tar.xz | |
firmware loader: fix races during loading firmware
This patch fixes two races in loading firmware:
1, FW_STATUS_DONE should be set before waking up the task waitting
on _request_firmware_load, otherwise FW_STATUS_ABORT may be
thought as DONE mistakenly.
2, Inside _request_firmware_load(), there is a small window between
wait_for_completion() and mutex_lock(&fw_lock), and 'echo 1 > loading'
still may happen during the period, so this patch checks FW_STATUS_DONE
to prevent pages' buffer completed from being freed in firmware_loading_store.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/firmware_class.c')
| -rw-r--r-- | drivers/base/firmware_class.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index 1cbefcfd15f7..1915ad821688 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -243,18 +243,21 @@ static ssize_t firmware_loading_store(struct device *dev, switch (loading) { case 1: /* discarding any previous partial load */ - for (i = 0; i < fw_priv->nr_pages; i++) - __free_page(fw_priv->pages[i]); - kfree(fw_priv->pages); - fw_priv->pages = NULL; - fw_priv->page_array_size = 0; - fw_priv->nr_pages = 0; - set_bit(FW_STATUS_LOADING, &fw_priv->status); + if (!test_bit(FW_STATUS_DONE, &fw_priv->status)) { + for (i = 0; i < fw_priv->nr_pages; i++) + __free_page(fw_priv->pages[i]); + kfree(fw_priv->pages); + fw_priv->pages = NULL; + fw_priv->page_array_size = 0; + fw_priv->nr_pages = 0; + set_bit(FW_STATUS_LOADING, &fw_priv->status); + } break; case 0: if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) { - complete(&fw_priv->completion); + set_bit(FW_STATUS_DONE, &fw_priv->status); clear_bit(FW_STATUS_LOADING, &fw_priv->status); + complete(&fw_priv->completion); break; } /* fallthrough */ @@ -557,7 +560,6 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent, wait_for_completion(&fw_priv->completion); - set_bit(FW_STATUS_DONE, &fw_priv->status); del_timer_sync(&fw_priv->timeout); mutex_lock(&fw_lock); |