linux-stable/fs/debugfs
Johannes Berg 952c3fce29 debugfs: fix wait/cancellation handling during remove
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>
2024-03-07 22:08:15 +00:00
..
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
file.c Merge branches 'acpi-pm', 'acpi-video', 'acpi-apei' and 'acpi-extlog' 2024-01-04 13:19:40 +01:00
inode.c debugfs: fix wait/cancellation handling during remove 2024-03-07 22:08:15 +00:00
internal.h Revert "debugfs: annotate debugfs handlers vs. removal with lockdep" 2023-12-04 07:43:16 +01:00