On Tue, Jan 17, 2017 at 03:35:05PM +0000, Jakub Kicinski wrote:
> Commit 5d47ec02c37e ("firmware: Correct handling of fw_state_wait()
> return value") made the assumption that any error returned from
> fw_state_wait_timeout() means FW load has to be aborted. This is
> incorrect, FW load only has to be aborted when load timed out or
> has been interrupted. Otherwise, if wait exited because of a wake
> up, the waking thread (in firmware_loading_store()) had already
> performed the clean up - deleted fw_buf from the pending list and
> set fw_priv->buf to NULL.
>
> Example NULL dereference which occurs because requsted firmware
> could not be found by UMH:
>
> nfp 0000:02:00.0: Direct firmware load for AMDA0081-0001.cat failed with
> error -2
> nfp 0000:02:00.0: Falling back to user helper
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
> IP: _request_firmware+0x7fd/0x910
> PGD 0
>
> Oops: 0000 [#1] PREEMPT SMP
> CPU: 4 PID: 1981 Comm: insmod Tainted: G O
> 4.10.0-rc3-perf-00404-g575a284323c2 #78
> Hardware name: Dell Inc. PowerEdge T630/0W9WXC, BIOS 1.2.10 03/10/2015
> task: ffff919b81a99a80 task.stack: ffffb3bac5668000
> RIP: 0010:_request_firmware+0x7fd/0x910
> RSP: 0018:ffffb3bac566b978 EFLAGS: 00010246
> RAX: 00000000fffffffe RBX: ffff919b9b2becc0 RCX: ffff919b9b2bece8
> RDX: ffff919b81a99a80 RSI: 0000000000000206 RDI: 0000000000000000
> RBP: ffffb3bac566b9e0 R08: ffff919b9f30f4b8 R09: 0000000000000002
> R10: 00000120d2b47b48 R11: 0000000000000000 R12: ffffb3bac566ba18
> R13: ffff919b823f4780 R14: ffff919b907c5000 R15: 0000000000003a98
> FS: 00007fae4d803740(0000) GS:ffff919b9f300000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000038 CR3: 00000008507b8000 CR4: 00000000001406e0
> Call Trace:
> request_firmware+0x37/0x50
> ...
>
> Fixes: 5d47ec02c37e ("firmware: Correct handling of fw_state_wait() return
> value")
> Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
> ---
> v2:
> - improve commit message.
> ---
> 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 4497d263209f..ce142e6b2c72 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -1020,7 +1020,7 @@ static int _request_firmware_load(struct firmware_priv
> *fw_priv,
> }
>
> retval = fw_state_wait_timeout(&buf->fw_st, timeout);
> - if (retval < 0) {
> + if (retval == -ETIMEDOUT || retval == -ERESTARTSYS) {
> mutex_lock(&fw_lock);
> fw_load_abort(fw_priv);
> mutex_unlock(&fw_lock);
This is a bit messy, two other similar issues were reported before
and upon review I suggested Patrick Bruenn's fix with a better commit
log seems best fit. Patrick sent a patch Jan 4, 2017 but never followed up
despite my feedback on a small change on the commit log message [0]. Can you
try that and if that fixes it can you adjust the commit log accordingly? Please
note the preferred solution would be:
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index b9ac348e8d33..c530f8b4af01 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -542,6 +542,8 @@ static struct firmware_priv *to_firmware_priv(struct device
*dev)
static void __fw_load_abort(struct firmware_buf *buf)
{
+ if (!buf)
+ return;
/*
* There is a small window in which user can write to 'loading'
* between loading done and disappearance of 'loading'
[0] https://http://lkml.kernel.org/r/20170104174227.go13...@wotan.suse.de
Luis
