System hang issue during hibernation resume due to del_gendisk

DISCUSSION Keith Busch 1 participant 1 message Nov 13, 2014 1 message not in the archive NVMe

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Keith Busch

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2014-11-13 15:39 UTC #1 lore raw

Quoted 9 lines · Sunad Bhandary

Quoted 3 lines
I knew calling del_gendisk from resume wouldn't work, which is why it's done in a work queue, and removed in another thread if the device is gone. That's still not okay?
If we resume the system from hibernation with the kernel commandline parameter pciehp.pciehp_force = 1, then the nvme_remove function is called instead of nvme_resume.
In this case del_gendisk is called on the same thread which leads to potential problems

Oh, so 'resume' is not getting called. I have to admit, I did not know pciehp could handle removing a device before resume was completed.

I don't think the problem is calling del_gendisk from this context. We just need to make sure the driver is not internally holding commands it is not going to complete before calling del_gendisk. Did you happen to test with this patch included?

http://git.infradead.org/users/willy/linux-nvme.git/commit/74bae7e0dd70f3eee05d577d3d25fbcd54af4228

del_gendisk can totally deadlock without it if your filesystem has dirty data. If you did have that commit, then I'm baffled.