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authorJunyong Sun <sunjy516@gmail.com>2020-03-03 10:36:08 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-03-18 12:31:26 +0100
commitbcfbd3523f3c6eea51a74d217a8ebc5463bcb7f4 (patch)
tree1f99c619693936013ad0092812cafbf7af8fbdd0 /drivers/base
parent4dfff3d55440a9f8726a0f7d62a9c33594b58b10 (diff)
firmware: fix a double abort case with fw_load_sysfs_fallback
fw_sysfs_wait_timeout may return err with -ENOENT at fw_load_sysfs_fallback and firmware is already in abort status, no need to abort again, so skip it. This issue is caused by concurrent situation like below: when thread 1# wait firmware loading, thread 2# may write -1 to abort loading and wakeup thread 1# before it timeout. so wait_for_completion_killable_timeout of thread 1# would return remaining time which is != 0 with fw_st->status FW_STATUS_ABORTED.And the results would be converted into err -ENOENT in __fw_state_wait_common and transfered to fw_load_sysfs_fallback in thread 1#. The -ENOENT means firmware status is already at ABORTED, so fw_load_sysfs_fallback no need to get mutex to abort again. ----------------------------- thread 1#,wait for loading fw_load_sysfs_fallback ->fw_sysfs_wait_timeout ->__fw_state_wait_common ->wait_for_completion_killable_timeout in __fw_state_wait_common, ... 93 ret = wait_for_completion_killable_timeout(&fw_st->completion, timeout); 94 if (ret != 0 && fw_st->status == FW_STATUS_ABORTED) 95 return -ENOENT; 96 if (!ret) 97 return -ETIMEDOUT; 98 99 return ret < 0 ? ret : 0; ----------------------------- thread 2#, write -1 to abort loading firmware_loading_store ->fw_load_abort ->__fw_load_abort ->fw_state_aborted ->__fw_state_set ->complete_all in __fw_state_set, ... 111 if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) 112 complete_all(&fw_st->completion); ------------------------------------------- BTW,the double abort issue would not cause kernel panic or create an issue, but slow down it sometimes.The change is just a minor optimization. Signed-off-by: Junyong Sun <sunjunyong@xiaomi.com> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/1583202968-28792-1-git-send-email-sunjunyong@xiaomi.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/firmware_loader/fallback.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index 8704e1bae175..1e9c96e3ed63 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -525,7 +525,7 @@ static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs,
}
retval = fw_sysfs_wait_timeout(fw_priv, timeout);
- if (retval < 0) {
+ if (retval < 0 && retval != -ENOENT) {
mutex_lock(&fw_lock);
fw_load_abort(fw_sysfs);
mutex_unlock(&fw_lock);