kernel/linux.git/fs/debugfs, branch v6.1.168

debugfs: fix automount d_fsdata usage

2024-01-20T10:50:04+00:00

[ Upstream commit 0ed04a1847a10297595ac24dc7d46b35fb35f90a ] debugfs_create_automount() stores a function pointer in d_fsdata, but since commit 7c8d469877b1 ("debugfs: add support for more elaborate ->d_fsdata") debugfs_release_dentry() will free it, now conditionally on DEBUGFS_FSDATA_IS_REAL_FOPS_BIT, but that's not set for the function pointer in automount. As a result, removing an automount dentry would attempt to free the function pointer. Luckily, the only user of this (tracing) never removes it. Nevertheless, it's safer if we just handle the fsdata in one way, namely either DEBUGFS_FSDATA_IS_REAL_FOPS_BIT or allocated. Thus, change the automount to allocate it, and use the real_fops in the data to indicate whether or not automount is filled, rather than adding a type tag. At least for now this isn't actually needed, but the next changes will require it. Also check in debugfs_file_get() that it gets only called on regular files, just to make things clearer. Acked-by: Greg Kroah-Hartman Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

debugfs: fix error when writing negative value to atomic_t debugfs file

2022-12-31T12:31:58+00:00

[ Upstream commit d472cf797c4e268613dbce5ec9b95d0bcae19ecb ] The simple attribute files do not accept a negative value since the commit 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()"), so we have to use a 64-bit value to write a negative value for a debugfs file created by debugfs_create_atomic_t(). This restores the previous behaviour by introducing DEFINE_DEBUGFS_ATTRIBUTE_SIGNED for a signed value. Link: https://lkml.kernel.org/r/20220919172418.45257-4-akinobu.mita@gmail.com Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()") Signed-off-by: Akinobu Mita Reported-by: Zhao Gongyi Reviewed-by: David Hildenbrand Reviewed-by: Greg Kroah-Hartman Cc: Alexander Viro Cc: Jonathan Corbet Cc: Oscar Salvador Cc: Rafael J. Wysocki Cc: Shuah Khan Cc: Wei Yongjun Cc: Yicong Yang Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

debugfs: use DEFINE_SHOW_ATTRIBUTE to define debugfs_regset32_fops

2022-09-24T13:00:48+00:00

Use DEFINE_SHOW_ATTRIBUTE helper macro to simplify the code. Signed-off-by: ChenXiaoSong Link: https://lore.kernel.org/r/20220923102554.2443452-1-chenxiaosong2@huawei.com Signed-off-by: Greg Kroah-Hartman

debugfs: Only clobber mode/uid/gid on remount if asked

2022-09-24T12:01:37+00:00

Users may have explicitly configured their debugfs permissions; we shouldn't overwrite those just because a second mount appeared. Only clobber if the options were provided at mount time. Existing behavior: ## Pre-existing status: debugfs is 0755. # chmod 755 /sys/kernel/debug/ # stat -c '%A' /sys/kernel/debug/ drwxr-xr-x ## New mount sets kernel-default permissions: # mount -t debugfs none /mnt/foo # stat -c '%A' /mnt/foo drwx------ ## Unexpected: the original mount changed permissions: # stat -c '%A' /sys/kernel/debug drwx------ New behavior: ## Pre-existing status: debugfs is 0755. # chmod 755 /sys/kernel/debug/ # stat -c '%A' /sys/kernel/debug/ drwxr-xr-x ## New mount inherits existing permissions: # mount -t debugfs none /mnt/foo # stat -c '%A' /mnt/foo drwxr-xr-x ## Expected: old mount is unchanged: # stat -c '%A' /sys/kernel/debug drwxr-xr-x Full test cases are being submitted to LTP. Signed-off-by: Brian Norris Link: https://lore.kernel.org/r/20220912163042.v3.1.Icbd40fce59f55ad74b80e5d435ea233579348a78@changeid Signed-off-by: Greg Kroah-Hartman

debugfs: add debugfs_lookup_and_remove()

2022-09-05T11:02:34+00:00

There is a very common pattern of using debugfs_remove(debufs_lookup(..)) which results in a dentry leak of the dentry that was looked up. Instead of having to open-code the correct pattern of calling dput() on the dentry, create debugfs_lookup_and_remove() to handle this pattern automatically and properly without any memory leaks. Cc: stable Reported-by: Kuyo Chang Tested-by: Kuyo Chang Link: https://lore.kernel.org/r/YxIaQ8cSinDR881k@kroah.com Signed-off-by: Greg Kroah-Hartman

debugfs: Document that debugfs_create functions need not be error checked

2022-02-25T10:56:13+00:00

As talked about in commit b792e64021ec ("drm: no need to check return value of debugfs_create functions"), in many cases we can get away with totally skipping checking the errors of debugfs functions. Let's document that so people don't add new code that needlessly checks these errors. Probably this note could be added to a boatload of functions, but that's a lot of duplication. Let's just add it to the two most frequent ones and hope people will get the idea. Suggested-by: Javier Martinez Canillas Reviewed-by: Javier Martinez Canillas Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20220222154555.1.I26d364db7a007f8995e8f0dac978673bc8e9f5e2@changeid Signed-off-by: Greg Kroah-Hartman

debugfs: lockdown: Allow reading debugfs files that are not world readable

2022-01-06T14:47:41+00:00

When the kernel is locked down the kernel allows reading only debugfs files with mode 444. Mode 400 is also valid but is not allowed. Make the 444 into a mask. Fixes: 5496197f9b08 ("debugfs: Restrict debugfs when the kernel is locked down") Signed-off-by: Michal Suchanek Link: https://lore.kernel.org/r/20220104170505.10248-1-msuchanek@suse.de Signed-off-by: Greg Kroah-Hartman

debugfs: debugfs_create_file_size(): use IS_ERR to check for error

2021-09-21T07:09:06+00:00

debugfs_create_file() returns encoded error so use IS_ERR for checking return value. Reviewed-by: Christian König Signed-off-by: Nirmoy Das Fixes: ff9fb72bc077 ("debugfs: return error values, not NULL") Cc: stable References: https://gitlab.freedesktop.org/drm/amd/-/issues/1686 Link: https://lore.kernel.org/r/20210902102917.2233-1-nirmoy.das@amd.com Signed-off-by: Greg Kroah-Hartman

debugfs: Return error during {full/open}_proxy_open() on rmmod

2021-08-05T12:42:40+00:00

If a kernel module gets unloaded then it printed report about a leak before commit 275678e7a9be ("debugfs: Check module state before warning in {full/open}_proxy_open()"). An additional check was added in this commit to avoid this printing. But it was forgotten that the function must return an error in this case because it was not actually opened. As result, the systems started to crash or to hang when a module was unloaded while something was trying to open a file. Fixes: 275678e7a9be ("debugfs: Check module state before warning in {full/open}_proxy_open()") Cc: Taehee Yoo Reported-by: Mário Lopes Signed-off-by: Sven Eckelmann Link: https://lore.kernel.org/r/20210802162444.7848-1-sven@narfation.org Signed-off-by: Greg Kroah-Hartman

Merge tag 'v5.13-rc6' into driver-core-next

2021-06-14T07:07:45+00:00

We need the driver core fix in here as well. Signed-off-by: Greg Kroah-Hartman