Messages in this thread | | | From | Linus Torvalds <> | Date | Sat, 24 Jul 2021 13:48:14 -0700 | Subject | Re: 5.14-rc failure to resume |
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On Sat, Jul 24, 2021 at 12:44 PM Jens Axboe <axboe@kernel.dk> wrote: > > This does appear to be the culprit. With it reverted on top of current > master (and with the block and io_uring changes pulled in too), the > kernel survives many resumes without issue.
That commit seems fundamentally buggy.
It makes "acpi_dev_get_next_match_dev()" always do
acpi_dev_put(adev);
to put the previous device, but "adev" is perfectly valid as NULL, and acpi_dev_get_next_match_dev() even tests for it:
struct device *start = adev ? &adev->dev : NULL;
so it can - and will - do
acpi_dev_put(NULL);
which does
put_device(&adev->dev);
and passes in an invalid pointer to put_device().
And yes, that adev very much can be NULL, with drivers/acpi/utils.c even passing it in explicitly:
struct acpi_device * acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv) { return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv); } EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
Am I missing something? How does that code work at all for anybody?
I probably _am_ missing something.
Linus
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