linux.git/fs/debugfs/file.c, branch v6.6.131

debugfs: fix automount d_fsdata usage

2024-01-20T10:51:37+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 __rcu type comparison warning

2023-11-20T10:59:26+00:00

[ Upstream commit 7360a48bd0f5e62b2d00c387d5d3f2821eb290ce ]

Sparse reports the following:

fs/debugfs/file.c:942:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
fs/debugfs/file.c:942:9: sparse:    char [noderef] __rcu *
fs/debugfs/file.c:942:9: sparse:    char *

rcu_assign_pointer() expects that it's assigning to pointers annotated
with __rcu. We can't annotate the generic struct file::private_data, so
cast it instead.

Fixes: 86b5488121db ("debugfs: Add write support to debugfs_create_str()")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202309091933.BRWlSnCq-lkp@intel.com/
Signed-off-by: Mike Tipton 
Link: https://lore.kernel.org/r/20230922134512.5126-1-quic_mdtipton@quicinc.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

debugfs: Add write support to debugfs_create_str()

2023-08-22T18:04:07+00:00

Currently, debugfs_create_str() only supports reading strings from
debugfs. Add support for writing them as well.

Based on original implementation by Peter Zijlstra [0]. Write support
was present in the initial patch version, but dropped in v2 due to lack
of users. We have a user now, so reintroduce it.

[0] https://lore.kernel.org/all/YF3Hv5zXb%2F6lauzs@hirez.programming.kicks-ass.net/

Signed-off-by: Mike Tipton 
Acked-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/r/20230807142914.12480-2-quic_mdtipton@quicinc.com
Signed-off-by: Georgi Djakov

debugfs: Correct the 'debugfs_create_str' docs

2023-05-31T18:02:14+00:00

The documentation of the 'debugfs_create_str' says that the function
returns a pointer to a dentry created, or an ERR_PTR in case of error.
Actually, this is not true: this function doesn't return anything at all.
Correct the documentation correspondingly.

Signed-off-by: Ivan Orlov 
Link: https://lore.kernel.org/r/20230514172353.52878-1-ivan.orlov0322@gmail.com
Signed-off-by: Greg Kroah-Hartman

debugfs: Export debugfs_create_str symbol

2023-01-20T11:41:00+00:00

Needed by SCMI Raw mode support when compiled as a loadable module.

Cc: Greg Kroah-Hartman 
Cc: "Rafael J. Wysocki" 
Signed-off-by: Cristian Marussi 
Tested-by: Florian Fainelli 
Tested-by: Vincent Guittot 
Acked-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/r/20230118121426.492864-10-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla

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

2022-12-01T00:13:16+00:00

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

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: 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: 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