linux.git/fs/debugfs/inode.c, branch v6.12.80 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git debugfs: fix mount options not being applied 2025-08-28T14:31:08+00:00 Charalampos Mitrodimas charmitro@posteo.net 2025-08-16T14:14:37+00:00 3adec7077192c85e4d819b19dbbbcec79d94233e commit ba6cc29351b1fa0cb9adce91b88b9f3c3cbe9c46 upstream. Mount options (uid, gid, mode) are silently ignored when debugfs is mounted. This is a regression introduced during the conversion to the new mount API. When the mount API conversion was done, the parsed options were never applied to the superblock when it was reused. As a result, the mount options were ignored when debugfs was mounted. Fix this by following the same pattern as the tracefs fix in commit e4d32142d1de ("tracing: Fix tracefs mount options"). Call debugfs_reconfigure() in debugfs_get_tree() to apply the mount options to the superblock after it has been created or reused. As an example, with the bug the "mode" mount option is ignored: $ mount -o mode=0666 -t debugfs debugfs /tmp/debugfs_test $ mount | grep debugfs_test debugfs on /tmp/debugfs_test type debugfs (rw,relatime) $ ls -ld /tmp/debugfs_test drwx------ 25 root root 0 Aug 4 14:16 /tmp/debugfs_test With the fix applied, it works as expected: $ mount -o mode=0666 -t debugfs debugfs /tmp/debugfs_test $ mount | grep debugfs_test debugfs on /tmp/debugfs_test type debugfs (rw,relatime,mode=666) $ ls -ld /tmp/debugfs_test drw-rw-rw- 37 root root 0 Aug 2 17:28 /tmp/debugfs_test Fixes: a20971c18752 ("vfs: Convert debugfs to use the new mount API") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220406 Cc: stable <stable@kernel.org> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Charalampos Mitrodimas <charmitro@posteo.net> Link: https://lore.kernel.org/r/20250816-debugfs-mount-opts-v3-1-d271dad57b5b@posteo.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ba6cc29351b1fa0cb9adce91b88b9f3c3cbe9c46 upstream.

Mount options (uid, gid, mode) are silently ignored when debugfs is
mounted. This is a regression introduced during the conversion to the
new mount API.

When the mount API conversion was done, the parsed options were never
applied to the superblock when it was reused. As a result, the mount
options were ignored when debugfs was mounted.

Fix this by following the same pattern as the tracefs fix in commit
e4d32142d1de ("tracing: Fix tracefs mount options"). Call
debugfs_reconfigure() in debugfs_get_tree() to apply the mount options
to the superblock after it has been created or reused.

As an example, with the bug the "mode" mount option is ignored:

  $ mount -o mode=0666 -t debugfs debugfs /tmp/debugfs_test
  $ mount | grep debugfs_test
  debugfs on /tmp/debugfs_test type debugfs (rw,relatime)
  $ ls -ld /tmp/debugfs_test
  drwx------ 25 root root 0 Aug  4 14:16 /tmp/debugfs_test

With the fix applied, it works as expected:

  $ mount -o mode=0666 -t debugfs debugfs /tmp/debugfs_test
  $ mount | grep debugfs_test
  debugfs on /tmp/debugfs_test type debugfs (rw,relatime,mode=666)
  $ ls -ld /tmp/debugfs_test
  drw-rw-rw- 37 root root 0 Aug  2 17:28 /tmp/debugfs_test

Fixes: a20971c18752 ("vfs: Convert debugfs to use the new mount API")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220406
Cc: stable <stable@kernel.org>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Charalampos Mitrodimas <charmitro@posteo.net>
Link: https://lore.kernel.org/r/20250816-debugfs-mount-opts-v3-1-d271dad57b5b@posteo.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
debugfs show actual source in /proc/mounts 2024-08-30T06:22:37+00:00 Marc Aurèle La France tsi@tuyoix.net 2024-08-10T19:25:27+00:00 3a987b88a42593875f6345188ca33731c7df728c After its conversion to the new mount API, debugfs displays "none" in /proc/mounts instead of the actual source. Fix this by recognising its "source" mount option. Signed-off-by: Marc Aurèle La France <tsi@tuyoix.net> Link: https://lore.kernel.org/r/e439fae2-01da-234b-75b9-2a7951671e27@tuyoix.net Fixes: a20971c18752 ("vfs: Convert debugfs to use the new mount API") Cc: stable@vger.kernel.org # 6.10.x: 49abee5991e1: debugfs: Convert to new uid/gid option parsing helpers Signed-off-by: Christian Brauner <brauner@kernel.org> 
After its conversion to the new mount API, debugfs displays "none" in
/proc/mounts instead of the actual source.  Fix this by recognising its
"source" mount option.

Signed-off-by: Marc Aurèle La France <tsi@tuyoix.net>
Link: https://lore.kernel.org/r/e439fae2-01da-234b-75b9-2a7951671e27@tuyoix.net
Fixes: a20971c18752 ("vfs: Convert debugfs to use the new mount API")
Cc: stable@vger.kernel.org # 6.10.x: 49abee5991e1: debugfs: Convert to new uid/gid option parsing helpers
Signed-off-by: Christian Brauner <brauner@kernel.org>
Merge tag 'vfs-6.11.mount.api' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs 2024-07-15T18:31:32+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-07-15T18:31:32+00:00 b8fc1bd73a5a12e48f9fd2e7ccea60cadf718c93 Pull vfs mount API updates from Christian Brauner: - Add a generic helper to parse uid and gid mount options. Currently we open-code the same logic in various filesystems which is error prone, especially since the verification of uid and gid mount options is a sensitive operation in the face of idmappings. Add a generic helper and convert all filesystems over to it. Make sure that filesystems that are mountable in unprivileged containers verify that the specified uid and gid can be represented in the owning namespace of the filesystem. - Convert hostfs to the new mount api. * tag 'vfs-6.11.mount.api' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fuse: Convert to new uid/gid option parsing helpers fuse: verify {g,u}id mount options correctly fat: Convert to new uid/gid option parsing helpers fat: Convert to new mount api fat: move debug into fat_mount_options vboxsf: Convert to new uid/gid option parsing helpers tracefs: Convert to new uid/gid option parsing helpers smb: client: Convert to new uid/gid option parsing helpers tmpfs: Convert to new uid/gid option parsing helpers ntfs3: Convert to new uid/gid option parsing helpers isofs: Convert to new uid/gid option parsing helpers hugetlbfs: Convert to new uid/gid option parsing helpers ext4: Convert to new uid/gid option parsing helpers exfat: Convert to new uid/gid option parsing helpers efivarfs: Convert to new uid/gid option parsing helpers debugfs: Convert to new uid/gid option parsing helpers autofs: Convert to new uid/gid option parsing helpers fs_parse: add uid & gid option option parsing helpers hostfs: Add const qualifier to host_root in hostfs_fill_super() hostfs: convert hostfs to use the new mount API 
Pull vfs mount API updates from Christian Brauner:

 - Add a generic helper to parse uid and gid mount options.

   Currently we open-code the same logic in various filesystems which is
   error prone, especially since the verification of uid and gid mount
   options is a sensitive operation in the face of idmappings.

   Add a generic helper and convert all filesystems over to it. Make
   sure that filesystems that are mountable in unprivileged containers
   verify that the specified uid and gid can be represented in the
   owning namespace of the filesystem.

 - Convert hostfs to the new mount api.

* tag 'vfs-6.11.mount.api' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fuse: Convert to new uid/gid option parsing helpers
  fuse: verify {g,u}id mount options correctly
  fat: Convert to new uid/gid option parsing helpers
  fat: Convert to new mount api
  fat: move debug into fat_mount_options
  vboxsf: Convert to new uid/gid option parsing helpers
  tracefs: Convert to new uid/gid option parsing helpers
  smb: client: Convert to new uid/gid option parsing helpers
  tmpfs: Convert to new uid/gid option parsing helpers
  ntfs3: Convert to new uid/gid option parsing helpers
  isofs: Convert to new uid/gid option parsing helpers
  hugetlbfs: Convert to new uid/gid option parsing helpers
  ext4: Convert to new uid/gid option parsing helpers
  exfat: Convert to new uid/gid option parsing helpers
  efivarfs: Convert to new uid/gid option parsing helpers
  debugfs: Convert to new uid/gid option parsing helpers
  autofs: Convert to new uid/gid option parsing helpers
  fs_parse: add uid & gid option option parsing helpers
  hostfs: Add const qualifier to host_root in hostfs_fill_super()
  hostfs: convert hostfs to use the new mount API
debugfs: Convert to new uid/gid option parsing helpers 2024-07-02T04:21:18+00:00 Eric Sandeen sandeen@redhat.com 2024-06-28T00:29:46+00:00 49abee5991e18f14ec822ef53acd173ae58ff594 Convert to new uid/gid option parsing helpers Signed-off-by: Eric Sandeen <sandeen@redhat.com> Link: https://lore.kernel.org/r/b2f44ee0-3cee-49eb-a416-f26a9306eb56@redhat.com Signed-off-by: Christian Brauner <brauner@kernel.org> 
Convert to new uid/gid option parsing helpers

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Link: https://lore.kernel.org/r/b2f44ee0-3cee-49eb-a416-f26a9306eb56@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
debugfs: continue to ignore unknown mount options 2024-05-28T12:32:42+00:00 Christian Brauner brauner@kernel.org 2024-05-27T12:15:22+00:00 0c07c273a5fe1a25d4f477fe7edf64b3e8b19b3d Wolfram reported that debugfs remained empty on some of his boards triggering the message "debugfs: Unknown parameter 'auto'". The root of the issue is that we ignored unknown mount options in the old mount api but we started rejecting unknown mount options in the new mount api. Continue to ignore unknown mount options to not regress userspace. Fixes: a20971c18752 ("vfs: Convert debugfs to use the new mount API") Link: https://lore.kernel.org/r/20240527100618.np2wqiw5mz7as3vk@ninjato Reported-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Christian Brauner <brauner@kernel.org> 
Wolfram reported that debugfs remained empty on some of his boards
triggering the message "debugfs: Unknown parameter 'auto'".

The root of the issue is that we ignored unknown mount options in the
old mount api but we started rejecting unknown mount options in the new
mount api. Continue to ignore unknown mount options to not regress
userspace.

Fixes: a20971c18752 ("vfs: Convert debugfs to use the new mount API")
Link: https://lore.kernel.org/r/20240527100618.np2wqiw5mz7as3vk@ninjato
Reported-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
vfs: Convert debugfs to use the new mount API 2024-03-26T08:04:54+00:00 David Howells dhowells@redhat.com 2024-03-05T23:08:39+00:00 a20971c187522f5a7cd8e961e7e9c88f31ea2bed Convert the debugfs filesystem to the new internal mount API as the old one will be obsoleted and removed. This allows greater flexibility in communication of mount parameters between userspace, the VFS and the filesystem. See Documentation/filesystems/mount_api.txt for more information. Signed-off-by: David Howells <dhowells@redhat.com> Co-developed-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> [sandeen: forward port to modern kernel, fix remounting] Link: https://lore.kernel.org/r/49d1f108-46e3-443f-85a3-6dd730c5d076@redhat.com cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> 
Convert the debugfs filesystem to the new internal mount API as the old
one will be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Signed-off-by: David Howells <dhowells@redhat.com>
Co-developed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
[sandeen: forward port to modern kernel, fix remounting]
Link: https://lore.kernel.org/r/49d1f108-46e3-443f-85a3-6dd730c5d076@redhat.com
cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
debugfs: fix wait/cancellation handling during remove 2024-03-07T22:08:15+00:00 Johannes Berg johannes.berg@intel.com 2024-02-29T14:36:20+00:00 952c3fce297f12c7ff59380adb66b564e2bc9b64 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: 8c88a474357e ("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> 
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: 8c88a474357e ("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>
Revert "debugfs: annotate debugfs handlers vs. removal with lockdep" 2023-12-04T06:43:16+00:00 Johannes Berg johannes.berg@intel.com 2023-12-02T10:49:37+00:00 88ac06a9f938c158bbeafec16adb483b0c66142f This reverts commit f4acfcd4deb1 ("debugfs: annotate debugfs handlers vs. removal with lockdep"), it appears to have false positives and really shouldn't have been in the -rc series with the fixes anyway. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Link: https://lore.kernel.org/r/20231202114936.fd55431ab160.I911aa53abeeca138126f690d383a89b13eb05667@changeid Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This reverts commit f4acfcd4deb1 ("debugfs: annotate debugfs handlers
vs. removal with lockdep"), it appears to have false positives and
really shouldn't have been in the -rc series with the fixes anyway.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20231202114936.fd55431ab160.I911aa53abeeca138126f690d383a89b13eb05667@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge tag 'wireless-2023-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless 2023-11-30T03:43:34+00:00 Jakub Kicinski kuba@kernel.org 2023-11-30T03:43:34+00:00 300fbb247eb3d2146b37c8dc127056f695091218 Johannes Berg says: ==================== wireless fixes: - debugfs had a deadlock (removal vs. use of files), fixes going through wireless ACKed by Greg - support for HT STAs on 320 MHz channels, even if it's not clear that should ever happen (that's 6 GHz), best not to WARN() - fix for the previous CQM fix that broke most cases - various wiphy locking fixes - various small driver fixes * tag 'wireless-2023-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless: wifi: mac80211: use wiphy locked debugfs for sdata/link wifi: mac80211: use wiphy locked debugfs helpers for agg_status wifi: cfg80211: add locked debugfs wrappers debugfs: add API to allow debugfs operations cancellation debugfs: annotate debugfs handlers vs. removal with lockdep debugfs: fix automount d_fsdata usage wifi: mac80211: handle 320 MHz in ieee80211_ht_cap_ie_to_sta_ht_cap wifi: avoid offset calculation on NULL pointer wifi: cfg80211: hold wiphy mutex for send_interface wifi: cfg80211: lock wiphy mutex for rfkill poll wifi: cfg80211: fix CQM for non-range use wifi: mac80211: do not pass AP_VLAN vif pointer to drivers during flush wifi: iwlwifi: mvm: fix an error code in iwl_mvm_mld_add_sta() wifi: mt76: mt7925: fix typo in mt7925_init_he_caps wifi: mt76: mt7921: fix 6GHz disabled by the missing default CLC config ==================== Link: https://lore.kernel.org/r/20231129150809.31083-3-johannes@sipsolutions.net Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Johannes Berg says:

====================
wireless fixes:
 - debugfs had a deadlock (removal vs. use of files),
   fixes going through wireless ACKed by Greg
 - support for HT STAs on 320 MHz channels, even if it's
   not clear that should ever happen (that's 6 GHz), best
   not to WARN()
 - fix for the previous CQM fix that broke most cases
 - various wiphy locking fixes
 - various small driver fixes

* tag 'wireless-2023-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless:
  wifi: mac80211: use wiphy locked debugfs for sdata/link
  wifi: mac80211: use wiphy locked debugfs helpers for agg_status
  wifi: cfg80211: add locked debugfs wrappers
  debugfs: add API to allow debugfs operations cancellation
  debugfs: annotate debugfs handlers vs. removal with lockdep
  debugfs: fix automount d_fsdata usage
  wifi: mac80211: handle 320 MHz in ieee80211_ht_cap_ie_to_sta_ht_cap
  wifi: avoid offset calculation on NULL pointer
  wifi: cfg80211: hold wiphy mutex for send_interface
  wifi: cfg80211: lock wiphy mutex for rfkill poll
  wifi: cfg80211: fix CQM for non-range use
  wifi: mac80211: do not pass AP_VLAN vif pointer to drivers during flush
  wifi: iwlwifi: mvm: fix an error code in iwl_mvm_mld_add_sta()
  wifi: mt76: mt7925: fix typo in mt7925_init_he_caps
  wifi: mt76: mt7921: fix 6GHz disabled by the missing default CLC config
====================

Link: https://lore.kernel.org/r/20231129150809.31083-3-johannes@sipsolutions.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
debugfs: add API to allow debugfs operations cancellation 2023-11-27T10:24:55+00:00 Johannes Berg johannes.berg@intel.com 2023-11-24T16:25:26+00:00 8c88a474357ead632b07c70bf7f119ace8c3b39e In some cases there might be longer-running hardware accesses in debugfs files, or attempts to acquire locks, and we want to still be able to quickly remove the files. Introduce a cancellations API to use inside the debugfs handler functions to be able to cancel such operations on a per-file basis. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
In some cases there might be longer-running hardware accesses
in debugfs files, or attempts to acquire locks, and we want
to still be able to quickly remove the files.

Introduce a cancellations API to use inside the debugfs handler
functions to be able to cancel such operations on a per-file
basis.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>