[alsa-devel] [PATCH] sound/pci/riptide or drivers/base/firmware: Fix a possible sleep-in-atomic bug
The riptide driver may sleep under a spinlock, and the function call path is: snd_riptide_prepare (acquire the spinlock) setsampleformat sendcmd riptide_reset try_to_load_firmware request_firmware _request_firmware (drivers/base/firmware_class.c) _request_firmware_prepare kzalloc(GFP_KERNEL) --> may sleep
To fix it, GFP_KERNEL is replaced with GFP_ATOMIC in _request_firmware_prepare. This bug is found by my static analysis tool and my code review.
Signed-off-by: Jia-Ju Bai baijiaju1990@163.com --- drivers/base/firmware_class.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index 4b57cf5..d89f676 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -1138,7 +1138,7 @@ static inline void kill_pending_fw_fallback_reqs(bool only_kill_custom) { } struct firmware_buf *buf; int ret;
- *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL); + *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_ATOMIC); if (!firmware) { dev_err(device, "%s: kmalloc(struct firmware) failed\n", __func__);
On Mon, 09 Oct 2017 04:13:16 +0200, Jia-Ju Bai wrote:
The riptide driver may sleep under a spinlock, and the function call path is: snd_riptide_prepare (acquire the spinlock) setsampleformat sendcmd riptide_reset try_to_load_firmware request_firmware _request_firmware (drivers/base/firmware_class.c) _request_firmware_prepare kzalloc(GFP_KERNEL) --> may sleep
To fix it, GFP_KERNEL is replaced with GFP_ATOMIC in _request_firmware_prepare. This bug is found by my static analysis tool and my code review.
Signed-off-by: Jia-Ju Bai baijiaju1990@163.com
This doesn't happen. try_to_load_firmware() aborts before the request_firmware() call when chip == NULL, which is the case from sendcmd().
And, moreover, the call of request_firmware() itself inside the spinlock would be already buggy.
thanks,
Takashi
drivers/base/firmware_class.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index 4b57cf5..d89f676 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -1138,7 +1138,7 @@ static inline void kill_pending_fw_fallback_reqs(bool only_kill_custom) { } struct firmware_buf *buf; int ret;
- *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
- *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_ATOMIC); if (!firmware) { dev_err(device, "%s: kmalloc(struct firmware) failed\n", __func__);
-- 1.7.9.5
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Thanks for your reply :) Yes, you are right. Sorry for this false positive.
Thanks, Jia-Ju Bai
On 2017/10/9 14:43, Takashi Iwai wrote:
On Mon, 09 Oct 2017 04:13:16 +0200, Jia-Ju Bai wrote:
The riptide driver may sleep under a spinlock, and the function call path is: snd_riptide_prepare (acquire the spinlock) setsampleformat sendcmd riptide_reset try_to_load_firmware request_firmware _request_firmware (drivers/base/firmware_class.c) _request_firmware_prepare kzalloc(GFP_KERNEL) --> may sleep
To fix it, GFP_KERNEL is replaced with GFP_ATOMIC in _request_firmware_prepare. This bug is found by my static analysis tool and my code review.
Signed-off-by: Jia-Ju Baibaijiaju1990@163.com
This doesn't happen. try_to_load_firmware() aborts before the request_firmware() call when chip == NULL, which is the case from sendcmd().
participants (2)
-
Jia-Ju Bai -
Takashi Iwai