Johannes Berg e88b5ae019 debugfs: fix wait/cancellation handling during remove ... [ Upstream commit 952c3fce29 ] Ben Greear further reports deadlocks during concurrent debugfs remove while files are being accessed, even though the code in question now uses debugfs cancellations. Turns out that despite all the review on the locking, we missed completely that the logic is wrong: if the refcount hits zero we can finish (and need not wait for the completion), but if it doesn't we have to trigger all the cancellations. As written, we can _never_ get into the loop triggering the cancellations. Fix this, and explain it better while at it. Cc: stable@vger.kernel.org Fixes: 8c88a47435 ("debugfs: add API to allow debugfs operations cancellation") Reported-by: Ben Greear <greearb@candelatech.com> Closes: https://lore.kernel.org/r/1c9fa9e5-09f1-0522-fdbc-dbcef4d255ca@candelatech.com Tested-by: Madhan Sai <madhan.singaraju@candelatech.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Link: https://lore.kernel.org/r/20240229153635.6bfab7eb34d3.I6c7aeff8c9d6628a8bc1ddcf332205a49d801f17@changeid Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-04-03 15:11:21 +02:00
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Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
file.c	debugfs: initialize cancellations earlier	2023-12-22 07:33:02 +01:00
inode.c	debugfs: fix wait/cancellation handling during remove	2024-04-03 15:11:21 +02:00
internal.h	Revert "debugfs: annotate debugfs handlers vs. removal with lockdep"	2023-12-04 07:43:16 +01:00