kernel/linux.git/fs/debugfs/file.c, branch v6.18.33

debugfs: fix placement of EXPORT_SYMBOL_GPL for debugfs_create_str()

2026-05-23T11:06:24+00:00

[ Upstream commit 4afc929c0f74c4f22b055a82b371d50586da58ca ] The EXPORT_SYMBOL_GPL() for debugfs_create_str was placed incorrectly away from the function definition. Move it immediately below the debugfs_create_str() function where it belongs. Fixes: d60b59b96795 ("debugfs: Export debugfs_create_str symbol") Signed-off-by: Gui-Dong Han Link: https://patch.msgid.link/20260323085930.88894-3-hanguidong02@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

debugfs: check for NULL pointer in debugfs_create_str()

2026-05-23T11:06:24+00:00

[ Upstream commit 31de83980d3764d784f79ff1bc93c42b324f4013 ] Passing a NULL pointer to debugfs_create_str() leads to a NULL pointer dereference when the debugfs file is read. Following upstream discussions, forbid the creation of debugfs string files with NULL pointers. Add a WARN_ON() to expose offending callers and return early. Fixes: 9af0440ec86e ("debugfs: Implement debugfs_create_str()") Reported-by: yangshiguang Closes: https://lore.kernel.org/lkml/2025122221-gag-malt-75ba@gregkh/ Suggested-by: Greg Kroah-Hartman Signed-off-by: Gui-Dong Han Link: https://patch.msgid.link/20260323085930.88894-2-hanguidong02@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

debugfs_get_aux(): allow storing non-const void *

2025-07-09T11:30:29+00:00

typechecking is up to users, anyway... Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20250702212616.GI3406663@ZenIV Signed-off-by: Greg Kroah-Hartman

debugfs: split short and full proxy wrappers, kill debugfs_real_fops()

2025-07-09T11:30:29+00:00

All users outside of fs/debugfs/file.c are gone, in there we can just fully split the wrappers for full and short cases and be done with that. Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20250702212419.GG3406663@ZenIV Signed-off-by: Greg Kroah-Hartman

debugfs: Fix the missing initializations in __debugfs_file_get()

2025-01-30T07:22:31+00:00

both method table pointers in debugfs_fsdata need to be initialized, obviously, and calculating the bitmap of present methods would also go better if we start with initialized state. Fixes: 41a0ecc0997c ("debugfs: get rid of dynamically allocation proxy_ops") Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20250129191937.GR1977892@ZenIV Signed-off-by: Greg Kroah-Hartman

debugfs: allow to store an additional opaque pointer at file creation

2025-01-15T12:14:36+00:00

Set by debugfs_create_file_aux(name, mode, parent, data, aux, fops). Plain debugfs_create_file() has it set to NULL. Accessed by debugfs_get_aux(file). Convenience macros for numeric opaque data - debugfs_create_file_aux_num and debugfs_get_aux_num, resp. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-5-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

debugfs: don't mess with bits in ->d_fsdata

2025-01-15T12:14:35+00:00

The reason we need that crap is the dual use ->d_fsdata has there - it's both holding a debugfs_fsdata reference after the first debugfs_file_get() (actually, after the call of proxy ->open()) *and* it serves as a place to stash a reference to real file_operations from object creation to the first open. Oh, and it's triple use, actually - that stashed reference might be to debugfs_short_fops. Bugger that for a game of solidiers - just put the operations reference into debugfs-private augmentation of inode. And split debugfs_full_file_operations into full and short cases, so that debugfs_get_file() could tell one from another. Voila - ->d_fsdata holds NULL until the first (successful) debugfs_get_file() and a reference to struct debugfs_fsdata afterwards. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-4-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

debugfs: get rid of dynamically allocation proxy_ops

2025-01-15T12:14:35+00:00

All it takes is having full_proxy_open() collect the information about available methods and store it in debugfs_fsdata. Wrappers are called only after full_proxy_open() has succeeded calling debugfs_get_file(), so they are guaranteed to have ->d_fsdata already pointing to debugfs_fsdata. As the result, they can check if method is absent and bugger off early, without any atomic operations, etc. - same effect as what we'd have from NULL method. Which makes the entire proxy_fops contents unconditional, making it completely pointless - we can just put those methods (unconditionally) into debugfs_full_proxy_file_operations and forget about dynamic allocation, replace_fops, etc. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-3-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

fs: debugfs: fix open proxy for unsafe files

2025-01-10T08:41:53+00:00

In the previous commit referenced below, I had to split the short fops handling into different proxy fops. This necessitated knowing out-of-band whether or not the ops are short or full, when attempting to convert from fops to allocated fsdata. Unfortunately, I only converted full_proxy_open() which is used for the new full_proxy_open_regular() and full_proxy_open_short(), but forgot about the call in open_proxy_open(), used for debugfs_create_file_unsafe(). Fix that, it never has short fops. Fixes: f8f25893a477 ("fs: debugfs: differentiate short fops with proxy ops") Reported-by: Suresh Kumar Kurmi Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202501101055.bb8bf3e7-lkp@intel.com Reported-by: Venkat Rao Bagalkote Signed-off-by: Johannes Berg Link: https://lore.kernel.org/r/20250110085826.cd74f3b7a36b.I430c79c82ec3f954c2ff9665753bf6ac9e63eef8@changeid Signed-off-by: Greg Kroah-Hartman

fs: debugfs: differentiate short fops with proxy ops

2025-01-07T15:20:08+00:00

Geert reported that my previous short fops debugfs changes broke m68k, because it only has mandatory alignement of two, so we can't stash the "is it short" information into the pointer (as we already did with the "is it real" bit.) Instead, exploit the fact that debugfs_file_get() called on an already open file will already find that the fsdata is no longer the real fops but rather the allocated data that already distinguishes full/short ops, so only open() needs to be able to distinguish. We can achieve that by using two different open functions. Unfortunately this requires another set of full file ops, increasing the size by 536 bytes (x86-64), but that's still a reasonable trade-off given that only converting some of the wireless stack gained over 28k. This brings the total cost of this to around 1k, for wins of 28k (all x86-64). Reported-and-tested-by: Geert Uytterhoeven Link: https://lore.kernel.org/CAMuHMdWu_9-L2Te101w8hU7H_2yobJFPXSwwUmGHSJfaPWDKiQ@mail.gmail.com Fixes: 8dc6d81c6b2a ("debugfs: add small file operations for most files") Signed-off-by: Johannes Berg Tested-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20241129121536.30989-2-johannes@sipsolutions.net Signed-off-by: Greg Kroah-Hartman