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2021-05-21debugfs: remove return value of debugfs_create_ulong()Greg Kroah-Hartman
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 <gregkh@linuxfoundation.org>
2021-05-21debugfs: remove return value of debugfs_create_bool()Greg Kroah-Hartman
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 <gregkh@linuxfoundation.org>
2021-04-16debugfs: Implement debugfs_create_str()Peter Zijlstra
Implement debugfs_create_str() to easily display names and such in debugfs. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Tested-by: Valentin Schneider <valentin.schneider@arm.com> Link: https://lkml.kernel.org/r/20210412102001.415407080@infradead.org
2020-10-30debugfs: remove return value of debugfs_create_devm_seqfile()Greg Kroah-Hartman
No one checks the return value of debugfs_create_devm_seqfile(), 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/20201023131037.2500765-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-10debugfs: make sure we can remove u32_array files cleanlyJakub Kicinski
debugfs_create_u32_array() allocates a small structure to wrap the data and size information about the array. If users ever try to remove the file this leads to a leak since nothing ever frees this wrapper. That said there are no upstream users of debugfs_create_u32_array() that'd remove a u32 array file (we only have one u32 array user in CMA), so there is no real bug here. Make callers pass a wrapper they allocated. This way the lifetime management of the wrapper is on the caller, and we can avoid the potential leak in debugfs. CC: Chucheng Luo <luochucheng@vivo.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-17debugfs: remove return value of debugfs_create_u32()Greg Kroah-Hartman
No one checks the return value of debugfs_create_u32(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20200416145448.GA1380878@kroah.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-01Merge branch 'linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto updates from Herbert Xu: "API: - Fix out-of-sync IVs in self-test for IPsec AEAD algorithms Algorithms: - Use formally verified implementation of x86/curve25519 Drivers: - Enhance hwrng support in caam - Use crypto_engine for skcipher/aead/rsa/hash in caam - Add Xilinx AES driver - Add uacce driver - Register zip engine to uacce in hisilicon - Add support for OCTEON TX CPT engine in marvell" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (162 commits) crypto: af_alg - bool type cosmetics crypto: arm[64]/poly1305 - add artifact to .gitignore files crypto: caam - limit single JD RNG output to maximum of 16 bytes crypto: caam - enable prediction resistance in HRWNG bus: fsl-mc: add api to retrieve mc version crypto: caam - invalidate entropy register during RNG initialization crypto: caam - check if RNG job failed crypto: caam - simplify RNG implementation crypto: caam - drop global context pointer and init_done crypto: caam - use struct hwrng's .init for initialization crypto: caam - allocate RNG instantiation descriptor with GFP_DMA crypto: ccree - remove duplicated include from cc_aead.c crypto: chelsio - remove set but not used variable 'adap' crypto: marvell - enable OcteonTX cpt options for build crypto: marvell - add the Virtual Function driver for CPT crypto: marvell - add support for OCTEON TX CPT engine crypto: marvell - create common Kconfig and Makefile for Marvell crypto: arm/neon - memzero_explicit aes-cbc key crypto: bcm - Use scnprintf() for avoiding potential buffer overflow crypto: atmel-i2c - Fix wakeup fail ...
2020-03-18debugfs: remove return value of debugfs_create_file_size()Greg Kroah-Hartman
No one checks the return value of debugfs_create_file_size, as it's not needed, so make the return value void, so that no one tries to do so in the future. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20200309163640.237984-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-22debugfs: regset32: Add Runtime PM supportGeert Uytterhoeven
Hardware registers of devices under control of power management cannot be accessed at all times. If such a device is suspended, register accesses may lead to undefined behavior, like reading bogus values, or causing exceptions or system lock-ups. Extend struct debugfs_regset32 with an optional field to let device drivers specify the device the registers in the set belong to. This allows debugfs_show_regset32() to make sure the device is resumed while its registers are being read. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-02-10debugfs: remove return value of debugfs_create_regset32()Greg Kroah-Hartman
No one checks the return value of debugfs_create_regset32(), 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/20191122104453.GA2017837@kroah.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-10simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystemsAl Viro
two requirements: no file creations in IS_DEADDIR and no cross-directory renames whatsoever. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-21debugfs: Fix !DEBUG_FS debugfs_create_automountKusanagi Kouichi
If DEBUG_FS=n, compile fails with the following error: kernel/trace/trace.c: In function 'tracing_init_dentry': kernel/trace/trace.c:8658:9: error: passing argument 3 of 'debugfs_create_automount' from incompatible pointer type [-Werror=incompatible-pointer-types] 8658 | trace_automount, NULL); | ^~~~~~~~~~~~~~~ | | | struct vfsmount * (*)(struct dentry *, void *) In file included from kernel/trace/trace.c:24: ./include/linux/debugfs.h:206:25: note: expected 'struct vfsmount * (*)(void *)' but argument is of type 'struct vfsmount * (*)(struct dentry *, void *)' 206 | struct vfsmount *(*f)(void *), | ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~ Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp> Link: https://lore.kernel.org/r/20191121102021787.MLMY.25002.ppp.dion.ne.jp@dmta0003.auone-net.jp Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-03debugfs: Add debugfs_create_xul() for hexadecimal unsigned longGeert Uytterhoeven
The existing debugfs_create_ulong() function supports objects of type "unsigned long", which are 32-bit or 64-bit depending on the platform, in decimal form. To format objects in hexadecimal, various debugfs_create_x*() functions exist, but all of them take fixed-size types. Add a debugfs helper for "unsigned long" objects in hexadecimal format. This avoids the need for users to open-code the same, or introduce bugs when casting the value pointer to "u32 *" or "u64 *" to call debugfs_create_x{32,64}(). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://lore.kernel.org/r/20191025094130.26033-2-geert+renesas@glider.be Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-03debugfs: remove return value of debugfs_create_atomic_t()Greg Kroah-Hartman
No one checks the return value of debugfs_create_atomic_t(), 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/20191016130332.GA28240@kroah.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-02debugfs: remove return value of debugfs_create_x8()Greg Kroah-Hartman
No one checks the return value of debugfs_create_x8(), 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/20191011132931.1186197-5-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-16debugfs: remove return value of debugfs_create_x64()Greg Kroah-Hartman
No one checks the return value of debugfs_create_x64(), 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/20191011132931.1186197-8-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-16debugfs: remove return value of debugfs_create_x32()Greg Kroah-Hartman
No one checks the return value of debugfs_create_x32(), 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/20191011132931.1186197-7-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-16debugfs: remove return value of debugfs_create_x16()Greg Kroah-Hartman
No one checks the return value of debugfs_create_x16(), 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/20191011132931.1186197-6-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-14debugfs: remove return value of debugfs_create_size_t()Greg Kroah-Hartman
No one checks the return value of debugfs_create_size_t(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20191011132931.1186197-4-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-14debugfs: remove return value of debugfs_create_u64()Greg Kroah-Hartman
No one checks the return value of debugfs_create_u64(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20191011132931.1186197-3-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-14debugfs: remove return value of debugfs_create_u16()Greg Kroah-Hartman
No one checks the return value of debugfs_create_u16(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20191011132931.1186197-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-14debugfs: remove return value of debugfs_create_u8()Greg Kroah-Hartman
No one checks the return value of debugfs_create_u8(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20191011132931.1186197-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-03debugfs: make debugfs_create_u32_array() return voidGreg Kroah-Hartman
The single user of debugfs_create_u32_array() does not care about the return value of it, so make it return void as there is no need to do anything with the return value. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-28debugfs: fix debugfs_real_fops() build errorArnd Bergmann
Some drivers use debugfs_real_fops() even when CONFIG_DEBUG_FS is disabled, which now leads to a build error: In file included from include/linux/list.h:9:0, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from drivers/net/wireless/broadcom/b43legacy/debugfs.c:26: drivers/net/wireless/broadcom/b43legacy/debugfs.c: In function 'b43legacy_debugfs_read': drivers/net/wireless/broadcom/b43legacy/debugfs.c:224:23: error: implicit declaration of function 'debugfs_real_fops'; did you mean 'debugfs_create_bool'? [-Werror=implicit-function-declaration] My first impulse was to add another 'static inline' dummy function returning NULL for it, which would work fine. However, most callers feed the pointer into container_of(), so it seems a little dangerous here. Since all the callers are inside of a read/write file operation that gets eliminated in this configuration, so having an 'extern' declaration seems better here. If it ever gets used in a dangerous way, that will now result in a link error. Fixes: 7c8d469877b1 ("debugfs: add support for more elaborate ->d_fsdata") Cc: Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Simon Horman <simon.horman@netronome.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-07debugfs: Remove redundant license textGreg Kroah-Hartman
Now that the SPDX tag is in all debugfs files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-07debugfs: add SPDX identifiers to all debugfs filesGreg Kroah-Hartman
It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the debugfs files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-07debugfs: purge obsolete SRCU based removal protectionNicolai Stange
Purge the SRCU based file removal race protection in favour of the new, refcount based debugfs_file_get()/debugfs_file_put() API. Fixes: 49d200deaa68 ("debugfs: prevent access to removed files' private data") Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-07debugfs: debugfs_real_fops(): drop __must_hold sparse annotationNicolai Stange
Currently, debugfs_real_fops() is annotated with a __must_hold(&debugfs_srcu) sparse annotation. With the conversion of the SRCU based protection of users against concurrent file removals to a per-file refcount based scheme, this becomes wrong. Drop this annotation. Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-07debugfs: implement per-file removal protectionNicolai Stange
Since commit 49d200deaa68 ("debugfs: prevent access to removed files' private data"), accesses to a file's private data are protected from concurrent removal by covering all file_operations with a SRCU read section and sychronizing with those before returning from debugfs_remove() by means of synchronize_srcu(). As pointed out by Johannes Berg, there are debugfs files with forever blocking file_operations. Their corresponding SRCU read side sections would block any debugfs_remove() forever as well, even unrelated ones. This results in a livelock. Because a remover can't cancel any indefinite blocking within foreign files, this is a problem. Resolve this by introducing support for more granular protection on a per-file basis. This is implemented by introducing an 'active_users' refcount_t to the per-file struct debugfs_fsdata state. At file creation time, it is set to one and a debugfs_remove() will drop that initial reference. The new debugfs_file_get() and debugfs_file_put(), intended to be used in place of former debugfs_use_file_start() and debugfs_use_file_finish(), increment and decrement it respectively. Once the count drops to zero, debugfs_file_put() will signal a completion which is possibly being waited for from debugfs_remove(). Thus, as long as there is a debugfs_file_get() not yet matched by a corresponding debugfs_file_put() around, debugfs_remove() will block. Actual users of debugfs_use_file_start() and -finish() will get converted to the new debugfs_file_get() and debugfs_file_put() by followup patches. Fixes: 49d200deaa68 ("debugfs: prevent access to removed files' private data") Reported-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-07debugfs: add support for more elaborate ->d_fsdataNicolai Stange
Currently, the user provided fops, "real_fops", are stored directly into ->d_fsdata. In order to be able to store more per-file state and thus prepare for more granular file removal protection, wrap the real_fops into a dynamically allocated container struct, debugfs_fsdata. A struct debugfs_fsdata gets allocated at file creation and freed from the newly intoduced ->d_release(). Finally, move the implementation of debugfs_real_fops() out of the public debugfs header such that struct debugfs_fsdata's declaration can be kept private. Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-17debugfs: Add dummy implementation of few helpersViresh Kumar
This adds (missing) dummy implementations of debugfs_create_file_unsafe() and debugfs_create_ulong(). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16fs: update location of filesystems documentationMauro Carvalho Chehab
The filesystem documentation was moved from DocBook to Documentation/filesystems/. Update it at the sources. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-04-08debugfs: set no_llseek in DEFINE_DEBUGFS_ATTRIBUTEGeliang Tang
In DEFINE_DEBUGFS_ATTRIBUTE() macro, since we use nonseekable_open() to open, we should use no_llseek() to seek, not generic_file_llseek(). Signed-off-by: Geliang Tang <geliangtang@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-23Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull namespace updates from Eric Biederman: "There is a lot here. A lot of these changes result in subtle user visible differences in kernel behavior. I don't expect anything will care but I will revert/fix things immediately if any regressions show up. From Seth Forshee there is a continuation of the work to make the vfs ready for unpriviled mounts. We had thought the previous changes prevented the creation of files outside of s_user_ns of a filesystem, but it turns we missed the O_CREAT path. Ooops. Pavel Tikhomirov and Oleg Nesterov worked together to fix a long standing bug in the implemenation of PR_SET_CHILD_SUBREAPER where only children that are forked after the prctl are considered and not children forked before the prctl. The only known user of this prctl systemd forks all children after the prctl. So no userspace regressions will occur. Holding earlier forked children to the same rules as later forked children creates a semantic that is sane enough to allow checkpoing of processes that use this feature. There is a long delayed change by Nikolay Borisov to limit inotify instances inside a user namespace. Michael Kerrisk extends the API for files used to maniuplate namespaces with two new trivial ioctls to allow discovery of the hierachy and properties of namespaces. Konstantin Khlebnikov with the help of Al Viro adds code that when a network namespace exits purges it's sysctl entries from the dcache. As in some circumstances this could use a lot of memory. Vivek Goyal fixed a bug with stacked filesystems where the permissions on the wrong inode were being checked. I continue previous work on ptracing across exec. Allowing a file to be setuid across exec while being ptraced if the tracer has enough credentials in the user namespace, and if the process has CAP_SETUID in it's own namespace. Proc files for setuid or otherwise undumpable executables are now owned by the root in the user namespace of their mm. Allowing debugging of setuid applications in containers to work better. A bug I introduced with permission checking and automount is now fixed. The big change is to mark the mounts that the kernel initiates as a result of an automount. This allows the permission checks in sget to be safely suppressed for this kind of mount. As the permission check happened when the original filesystem was mounted. Finally a special case in the mount namespace is removed preventing unbounded chains in the mount hash table, and making the semantics simpler which benefits CRIU. The vfs fix along with related work in ima and evm I believe makes us ready to finish developing and merge fully unprivileged mounts of the fuse filesystem. The cleanups of the mount namespace makes discussing how to fix the worst case complexity of umount. The stacked filesystem fixes pave the way for adding multiple mappings for the filesystem uids so that efficient and safer containers can be implemented" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc/sysctl: Don't grab i_lock under sysctl_lock. vfs: Use upper filesystem inode in bprm_fill_uid() proc/sysctl: prune stale dentries during unregistering mnt: Tuck mounts under others instead of creating shadow/side mounts. prctl: propagate has_child_subreaper flag to every descendant introduce the walk_process_tree() helper nsfs: Add an ioctl() to return owner UID of a userns fs: Better permission checking for submounts exit: fix the setns() && PR_SET_CHILD_SUBREAPER interaction vfs: open() with O_CREAT should not create inodes with unknown ids nsfs: Add an ioctl() to return the namespace type proc: Better ownership of files for non-dumpable tasks in user namespaces exec: Remove LSM_UNSAFE_PTRACE_CAP exec: Test the ptracer's saved cred to see if the tracee can gain caps exec: Don't reset euid and egid when the tracee has CAP_SETUID inotify: Convert to using per-namespace limits
2017-02-22Merge tag 'driver-core-4.11-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the "small" driver core patches for 4.11-rc1. Not much here, some firmware documentation and self-test updates, a debugfs code formatting issue, and a new feature for call_usermodehelper to make it more robust on systems that want to lock it down in a more secure way. All of these have been linux-next for a while now with no reported issues" * tag 'driver-core-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: kernfs: handle null pointers while printing node name and path Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper() Make static usermode helper binaries constant kmod: make usermodehelper path a const string firmware: revamp firmware documentation selftests: firmware: send expected errors to /dev/null selftests: firmware: only modprobe if driver is missing platform: Print the resource range if device failed to claim kref: prefer atomic_inc_not_zero to atomic_add_unless debugfs: improve formatting of debugfs_real_fops()
2017-02-02debugfs: add debugfs_lookup()Omar Sandoval
We don't always have easy access to the dentry of a file or directory we created in debugfs. Add a helper which allows us to get a dentry we previously created. The motivation for this change is a problem with blktrace and the blk-mq debugfs entries introduced in 07e4fead45e6 ("blk-mq: create debugfs directory tree"). Namely, in some cases, the directory that blktrace needs to create may already exist, but in other cases, it may not. We _could_ rely on a bunch of implied knowledge to decide whether to create the directory or not, but it's much cleaner on our end to just look it up. Signed-off-by: Omar Sandoval <osandov@fb.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02fs: Better permission checking for submountsEric W. Biederman
To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the mount namespace, and a test to see if the user is allowed to access the specified filesystem. The automount case is special in that mounting the original filesystem grants permission to mount the sub-filesystems, to any user who happens to stumble across the their mountpoint and satisfies the ordinary filesystem permission checks. Attempting to handle the automount case by using override_creds almost works. It preserves the idea that permission to mount the original filesystem is permission to mount the sub-filesystem. Unfortunately using override_creds messes up the filesystems ordinary permission checks. Solve this by being explicit that a mount is a submount by introducing vfs_submount, and using it where appropriate. vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let sget and friends know that a mount is a submount so they can take appropriate action. sget and sget_userns are modified to not perform any permission checks on submounts. follow_automount is modified to stop using override_creds as that has proven problemantic. do_mount is modified to always remove the new MS_SUBMOUNT flag so that we know userspace will never by able to specify it. autofs4 is modified to stop using current_real_cred that was put in there to handle the previous version of submount permission checking. cifs is modified to pass the mountpoint all of the way down to vfs_submount. debugfs is modified to pass the mountpoint all of the way down to trace_automount by adding a new parameter. To make this change easier a new typedef debugfs_automount_t is introduced to capture the type of the debugfs automount function. Cc: stable@vger.kernel.org Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid") Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-01-11debugfs: improve formatting of debugfs_real_fops()Jakub Kicinski
Type of debugfs_real_fops() is longer than parameters and the name, so there is no way to break the declaration nicely. We have to go over 80 characters. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-12-13Merge tag 'driver-core-4.10-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here's the new driver core patches for 4.10-rc1. Big thing here is the nice addition of "functional dependencies" to the driver core. The idea has been talked about for a very long time, great job to Rafael for stepping up and implementing it. It's been tested for longer than the 4.9-rc1 date, we held off on merging it earlier in order to feel more comfortable about it. Other than that, it's just a handful of small other patches, some good cleanups to the mess that is the firmware class code, and we have a test driver for the deferred probe logic. All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (30 commits) firmware: Correct handling of fw_state_wait() return value driver core: Silence device links sphinx warning firmware: remove warning at documentation generation time drivers: base: dma-mapping: Fix typo in dmam_alloc_non_coherent comments driver core: test_async: fix up typo found by 0-day firmware: move fw_state_is_done() into UHM section firmware: do not use fw_lock for fw_state protection firmware: drop bit ops in favor of simple state machine firmware: refactor loading status firmware: fix usermode helper fallback loading driver core: firmware_class: convert to use class_groups driver core: devcoredump: convert to use class_groups driver core: class: add class_groups support kernfs: Declare two local data structures static driver-core: fix platform_no_drv_owner.cocci warnings drivers/base/memory.c: Remove unused 'first_page' variable driver core: add CLASS_ATTR_WO() drivers: base: cacheinfo: support DT overrides for cache properties drivers: base: cacheinfo: add pr_fmt logging drivers: base: cacheinfo: fix boot error message when acpi is enabled ...
2016-11-04debugfs: constify argument to debugfs_real_fops()Jakub Kicinski
seq_file users can only access const version of file pointer, because the ->file member of struct seq_operations is marked as such. Make parameter to debugfs_real_fops() const. CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> CC: Nicolai Stange <nicstange@gmail.com> CC: Christian Lamparter <chunkeey@gmail.com> CC: LKML <linux-kernel@vger.kernel.org> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-28debugfs: improve DEFINE_DEBUGFS_ATTRIBUTE for !CONFIG_DEBUG_FSArnd Bergmann
The slp_s0_residency_usec debugfs file currently uses DEFINE_DEBUGFS_ATTRIBUTE(), but that macro cannot really be used to define files outside of the debugfs code, as it has no reference to the get/set functions if CONFIG_DEBUG_FS is not defined: drivers/platform/x86/intel_pmc_core.c:80:12: error: ‘pmc_core_dev_state_get’ defined but not used [-Werror=unused-function] This fixes the macro to always contain the reference, and instead rely on the stubbed-out debugfs_create_file to not actually refer to its arguments so the compiler can still drop the reference. This works because the attribute definition is always 'static', and the dead-code removal silently drops all static symbols that are not used. Fixes: c64688081490 ("debugfs: add support for self-protecting attribute file fops") Fixes: df2294fb6428 ("intel_pmc_core: Convert to DEFINE_DEBUGFS_ATTRIBUTE") Signed-off-by: Arnd Bergmann <arnd@arndb.de> [nicstange@gmail.com: Add dummy implementations of debugfs_attr_read() and debugfs_attr_write() in order to protect against possibly broken dead code elimination and to improve readability. Correct CONFIG_DEBUGFS_FS -> CONFIG_DEBUG_FS typo in changelog.] Signed-off-by: Nicolai Stange <nicstange@gmail.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-21debugfs: introduce a public file_operations accessorChristian Lamparter
This patch introduces an accessor which can be used by the users of debugfs (drivers, fs, ...) to get the original file_operations struct. It also removes the REAL_FOPS_DEREF macro in file.c and converts the code to use the public version. Previously, REAL_FOPS_DEREF was only available within the file.c of debugfs. But having a public getter available for debugfs users is important as some drivers (carl9170 and b43) use the pointer of the original file_operations in conjunction with container_of() within their debugfs implementations. Reviewed-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Christian Lamparter <chunkeey@gmail.com> Cc: stable <stable@vger.kernel.org> # 4.7+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-04-12debugfs: add support for self-protecting attribute file fopsNicolai Stange
In order to protect them against file removal issues, debugfs_create_file() creates a lifetime managing proxy around each struct file_operations handed in. In cases where this struct file_operations is able to manage file lifetime by itself already, the proxy created by debugfs is a waste of resources. The most common class of struct file_operations given to debugfs are those defined by means of the DEFINE_SIMPLE_ATTRIBUTE() macro. Introduce a DEFINE_DEBUGFS_ATTRIBUTE() macro to allow any struct file_operations of this class to be easily made file lifetime aware and thus, to be operated unproxied. Specifically, introduce debugfs_attr_read() and debugfs_attr_write() which wrap simple_attr_read() and simple_attr_write() under the protection of a debugfs_use_file_start()/debugfs_use_file_finish() pair. Make DEFINE_DEBUGFS_ATTRIBUTE() set the defined struct file_operations' ->read() and ->write() members to these wrappers. Export debugfs_create_file_unsafe() in order to allow debugfs users to create their files in non-proxying operation mode. Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-04-12debugfs: prevent access to removed files' private dataNicolai Stange
Upon return of debugfs_remove()/debugfs_remove_recursive(), it might still be attempted to access associated private file data through previously opened struct file objects. If that data has been freed by the caller of debugfs_remove*() in the meanwhile, the reading/writing process would either encounter a fault or, if the memory address in question has been reassigned again, unrelated data structures could get overwritten. However, since debugfs files are seldomly removed, usually from module exit handlers only, the impact is very low. Currently, there are ~1000 call sites of debugfs_create_file() spread throughout the whole tree and touching all of those struct file_operations in order to make them file removal aware by means of checking the result of debugfs_use_file_start() from within their methods is unfeasible. Instead, wrap the struct file_operations by a lifetime managing proxy at file open: - In debugfs_create_file(), the original fops handed in has got stashed away in ->d_fsdata already. - In debugfs_create_file(), install a proxy file_operations factory, debugfs_full_proxy_file_operations, at ->i_fop. This proxy factory has got an ->open() method only. It carries out some lifetime checks and if successful, dynamically allocates and sets up a new struct file_operations proxy at ->f_op. Afterwards, it forwards to the ->open() of the original struct file_operations in ->d_fsdata, if any. The dynamically set up proxy at ->f_op has got a lifetime managing wrapper set for each of the methods defined in the original struct file_operations in ->d_fsdata. Its ->release()er frees the proxy again and forwards to the original ->release(), if any. In order not to mislead the VFS layer, it is strictly necessary to leave those fields blank in the proxy that have been NULL in the original struct file_operations also, i.e. aren't supported. This is why there is a need for dynamically allocated proxies. The choice made not to allocate a proxy instance for every dentry at file creation, but for every struct file object instantiated thereof is justified by the expected usage pattern of debugfs, namely that in general very few files get opened more than once at a time. The wrapper methods set in the struct file_operations implement lifetime managing by means of the SRCU protection facilities already in place for debugfs: They set up a SRCU read side critical section and check whether the dentry is still alive by means of debugfs_use_file_start(). If so, they forward the call to the original struct file_operation stored in ->d_fsdata, still under the protection of the SRCU read side critical section. This SRCU read side critical section prevents any pending debugfs_remove() and friends to return to their callers. Since a file's private data must only be freed after the return of debugfs_remove(), the ongoing proxied call is guarded against any file removal race. If, on the other hand, the initial call to debugfs_use_file_start() detects that the dentry is dead, the wrapper simply returns -EIO and does not forward the call. Note that the ->poll() wrapper is special in that its signature does not allow for the return of arbitrary -EXXX values and thus, POLLHUP is returned here. In order not to pollute debugfs with wrapper definitions that aren't ever needed, I chose not to define a wrapper for every struct file_operations method possible. Instead, a wrapper is defined only for the subset of methods which are actually set by any debugfs users. Currently, these are: ->llseek() ->read() ->write() ->unlocked_ioctl() ->poll() The ->release() wrapper is special in that it does not protect the original ->release() in any way from dead files in order not to leak resources. Thus, any ->release() handed to debugfs must implement file lifetime management manually, if needed. For only 33 out of a total of 434 releasers handed in to debugfs, it could not be verified immediately whether they access data structures that might have been freed upon a debugfs_remove() return in the meanwhile. Export debugfs_use_file_start() and debugfs_use_file_finish() in order to allow any ->release() to manually implement file lifetime management. For a set of common cases of struct file_operations implemented by the debugfs_core itself, future patches will incorporate file lifetime management directly within those in order to allow for their unproxied operation. Rename the original, non-proxying "debugfs_create_file()" to "debugfs_create_file_unsafe()" and keep it for future internal use by debugfs itself. Factor out code common to both into the new __debugfs_create_file(). Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-04-12debugfs: prevent access to possibly dead file_operations at file openNicolai Stange
Nothing prevents a dentry found by path lookup before a return of __debugfs_remove() to actually get opened after that return. Now, after the return of __debugfs_remove(), there are no guarantees whatsoever regarding the memory the corresponding inode's file_operations object had been kept in. Since __debugfs_remove() is seldomly invoked, usually from module exit handlers only, the race is hard to trigger and the impact is very low. A discussion of the problem outlined above as well as a suggested solution can be found in the (sub-)thread rooted at http://lkml.kernel.org/g/20130401203445.GA20862@ZenIV.linux.org.uk ("Yet another pipe related oops.") Basically, Greg KH suggests to introduce an intermediate fops and Al Viro points out that a pointer to the original ones may be stored in ->d_fsdata. Follow this line of reasoning: - Add SRCU as a reverse dependency of DEBUG_FS. - Introduce a srcu_struct object for the debugfs subsystem. - In debugfs_create_file(), store a pointer to the original file_operations object in ->d_fsdata. - Make debugfs_remove() and debugfs_remove_recursive() wait for a SRCU grace period after the dentry has been delete()'d and before they return to their callers. - Introduce an intermediate file_operations object named "debugfs_open_proxy_file_operations". It's ->open() functions checks, under the protection of a SRCU read lock, whether the dentry is still alive, i.e. has not been d_delete()'d and if so, tries to acquire a reference on the owning module. On success, it sets the file object's ->f_op to the original file_operations and forwards the ongoing open() call to the original ->open(). - For clarity, rename the former debugfs_file_operations to debugfs_noop_file_operations -- they are in no way canonical. The choice of SRCU over "normal" RCU is justified by the fact, that the former may also be used to protect ->i_private data from going away during the execution of a file's readers and writers which may (and do) sleep. Finally, introduce the fs/debugfs/internal.h header containing some declarations internal to the debugfs implementation. Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07debugfs: Add stub function for debugfs_create_automount().Jiaxing Wang
Add stub for debugfs_create_automount() for when debugfs is not configured in. Signed-off-by: Jiaxing Wang <hello.wjx@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-18debugfs: Add debugfs_create_ulong()Viresh Kumar
Add debugfs_create_ulong() for the users of type 'unsigned long'. These will be 32 bits long on a 32 bit machine and 64 bits long on a 64 bit machine. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04debugfs: Pass bool pointer to debugfs_create_bool()Viresh Kumar
Its a bit odd that debugfs_create_bool() takes 'u32 *' as an argument, when all it needs is a boolean pointer. It would be better to update this API to make it accept 'bool *' instead, as that will make it more consistent and often more convenient. Over that bool takes just a byte. That required updates to all user sites as well, in the same commit updating the API. regmap core was also using debugfs_{read|write}_file_bool(), directly and variable types were updated for that to be bool as well. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-20debugfs: Export bool read/write functionsRichard Fitzgerald
The file read/write functions for bools have no special dependencies on debugfs internals and are sufficiently non-trivial to be worth exporting so clients can re-use the implementation. Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-05-10debugfs: switch to simple_follow_link()Al Viro
Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>