linux.git/fs/debugfs/file.c, 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: 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

debugfs: Fix debugfs_read_file_str()

2021-06-04T13:01:08+00:00

Read the entire size of the buffer, including the trailing new line
character.
Discovered while reading the sched domain names of CPU0:

before:

cat /sys/kernel/debug/sched/domains/cpu0/domain*/name
SMTMCDIE

after:

cat /sys/kernel/debug/sched/domains/cpu0/domain*/name
SMT
MC
DIE

Fixes: 9af0440ec86eb ("debugfs: Implement debugfs_create_str()")
Reviewed-by: Steven Rostedt (VMware) 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Dietmar Eggemann 
Link: https://lore.kernel.org/r/20210527091105.258457-1-dietmar.eggemann@arm.com
Signed-off-by: Greg Kroah-Hartman

debugfs: remove return value of debugfs_create_ulong()

2021-05-21T18:59:55+00:00

No one checks the return value of debugfs_create_ulong(), as it's not
needed, so make the return value void, so that no one tries to do so in
the future.

Link: https://lore.kernel.org/r/20210521184340.1348539-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

debugfs: remove return value of debugfs_create_bool()

2021-05-21T18:59:03+00:00

No one checks the return value of debugfs_create_bool(), as it's not
needed, so make the return value void, so that no one tries to do so in
the future.

Link: https://lore.kernel.org/r/20210521184519.1356639-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

debugfs: only accept read attributes for blobs

2021-05-14T11:36:18+00:00

Blobs can only be read. So, keep only 'read' file attributes because the
others will not work and only confuse users.

Signed-off-by: Wolfram Sang 
Link: https://lore.kernel.org/r/20210504131350.46586-1-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman