Hi Sergei,
Le sam. 23 janv. 2021 à 19:41, Sergei Shtylyov
<sergei.shtylyov@xxxxxxxxx> a écrit :
On 1/23/21 5:24 PM, Paul Cercueil wrote:
musb_queue_resume_work() would call the provided callback if the
runtime
PM status was 'active'. Otherwise, it would enqueue the request if
the
hardware was still suspended (musb->is_runtime_suspended is true).
This causes a race with the runtime PM handlers, as it is possible
to be
in the case where the runtime PM status is not yet 'active', but the
hardware has been awaken (PM resume function has been called).
Awakened. :-)
Oops. Hopefully Bin or Greg can fix it when merging (if I don't need to
v2, that is to say - feedback welcome).
Cheers,
-Paul
When hitting the race, the resume work was not enqueued, which
probably
triggered other bugs further down the stack. For instance, a telnet
connection on Ingenic SoCs would result in a 50/50 chance of a
segmentation fault somewhere in the musb code.
Rework the code so that either we call the callback directly if
(musb->is_runtime_suspended == 0), or enqueue the query otherwise.
Fixes: ea2f35c01d5e ("usb: musb: Fix sleeping function called from
invalid context for hdrc glue")
Cc: stable@xxxxxxxxxxxxxxx # v4.9+
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
Reviewed-by: Tony Lindgren <tony@xxxxxxxxxxx>
Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
[...]
MBR, Sergei
