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2022-09-08tracefs: Only clobber mode/uid/gid on remount if askedBrian Norris
Users may have explicitly configured their tracefs permissions; we shouldn't overwrite those just because a second mount appeared. Only clobber if the options were provided at mount time. Note: the previous behavior was especially surprising in the presence of automounted /sys/kernel/debug/tracing/. Existing behavior: ## Pre-existing status: tracefs is 0755. # stat -c '%A' /sys/kernel/tracing/ drwxr-xr-x ## (Re)trigger the automount. # umount /sys/kernel/debug/tracing # stat -c '%A' /sys/kernel/debug/tracing/. drwx------ ## Unexpected: the automount changed mode for other mount instances. # stat -c '%A' /sys/kernel/tracing/ drwx------ New behavior (after this change): ## Pre-existing status: tracefs is 0755. # stat -c '%A' /sys/kernel/tracing/ drwxr-xr-x ## (Re)trigger the automount. # umount /sys/kernel/debug/tracing # stat -c '%A' /sys/kernel/debug/tracing/. drwxr-xr-x ## Expected: the automount does not change other mount instances. # stat -c '%A' /sys/kernel/tracing/ drwxr-xr-x Link: https://lkml.kernel.org/r/20220826174353.2.Iab6e5ea57963d6deca5311b27fb7226790d44406@changeid Cc: stable@vger.kernel.org Fixes: 4282d60689d4f ("tracefs: Add new tracefs file system") Signed-off-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-06-17tracefs: Fix syntax errors in commentsXiang wangx
Delete the redundant word 'to'. Link: https://lkml.kernel.org/r/20220605092729.13010-1-wangxiang@cdjrlc.com Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-25tracefs: Set the group ownership in apply_options() not parse_options()Steven Rostedt (Google)
Al Viro brought it to my attention that the dentries may not be filled when the parse_options() is called, causing the call to set_gid() to possibly crash. It should only be called if parse_options() succeeds totally anyway. He suggested the logical place to do the update is in apply_options(). Link: https://lore.kernel.org/all/20220225165219.737025658@goodmis.org/ Link: https://lkml.kernel.org/r/20220225153426.1c4cab6b@gandalf.local.home Cc: stable@vger.kernel.org Acked-by: Al Viro <viro@zeniv.linux.org.uk> Reported-by: Al Viro <viro@zeniv.linux.org.uk> Fixes: 48b27b6b5191 ("tracefs: Set all files to the same group ownership as the mount option") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-01-16Merge tag 'trace-v5.17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "New: - The Real Time Linux Analysis (RTLA) tool is added to the tools directory. - Can safely filter on user space pointers with: field.ustring ~ "match-string" - eprobes can now be filtered like any other event. - trace_marker(_raw) now uses stream_open() to allow multiple threads to safely write to it. Note, this could possibly break existing user space, but we will not know until we hear about it, and then can revert the change if need be. - New field in events to display when bottom halfs are disabled. - Sorting of the ftrace functions are now done at compile time instead of at bootup. Infrastructure changes to support future efforts: - Added __rel_loc type for trace events. Similar to __data_loc but the offset to the dynamic data is based off of the location of the descriptor and not the beginning of the event. Needed for user defined events. - Some simplification of event trigger code. - Make synthetic events process its callback better to not hinder other event callbacks that are registered. Needed for user defined events. And other small fixes and cleanups" * tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits) tracing: Add ustring operation to filtering string pointers rtla: Add rtla timerlat hist documentation rtla: Add rtla timerlat top documentation rtla: Add rtla timerlat documentation rtla: Add rtla osnoise hist documentation rtla: Add rtla osnoise top documentation rtla: Add rtla osnoise man page rtla: Add Documentation rtla/timerlat: Add timerlat hist mode rtla: Add timerlat tool and timelart top mode rtla/osnoise: Add the hist mode rtla/osnoise: Add osnoise top mode rtla: Add osnoise tool rtla: Helper functions for rtla rtla: Real-Time Linux Analysis tool tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails tracing: Remove duplicate warnings when calling trace_create_file() tracing/kprobes: 'nmissed' not showed correctly for kretprobe tracing: Add test for user space strings when filtering on string pointers tracing: Have syscall trace events use trace_event_buffer_lock_reserve() ...
2021-12-11tracefs: Use d_inode() helper function to get the dentry inodeSteven Rostedt (VMware)
Instead of referencing the inode from a dentry via dentry->d_inode, use the helper function d_inode(dentry) instead. This is the considered the correct way to access it. Reported-by: Christian Brauner <christian.brauner@ubuntu.com> Reported: https://lore.kernel.org/all/20211208104454.nhxyvmmn6d2qhpwl@wittgenstein/ Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-12-08tracefs: Set all files to the same group ownership as the mount optionSteven Rostedt (VMware)
As people have been asking to allow non-root processes to have access to the tracefs directory, it was considered best to only allow groups to have access to the directory, where it is easier to just set the tracefs file system to a specific group (as other would be too dangerous), and that way the admins could pick which processes would have access to tracefs. Unfortunately, this broke tooling on Android that expected the other bit to be set. For some special cases, for non-root tools to trace the system, tracefs would be mounted and change the permissions of the top level directory which gave access to all running tasks permission to the tracing directory. Even though this would be dangerous to do in a production environment, for testing environments this can be useful. Now with the new changes to not allow other (which is still the proper thing to do), it breaks the testing tooling. Now more code needs to be loaded on the system to change ownership of the tracing directory. The real solution is to have tracefs honor the gid=xxx option when mounting. That is, (tracing group tracing has value 1003) mount -t tracefs -o gid=1003 tracefs /sys/kernel/tracing should have it that all files in the tracing directory should be of the given group. Copy the logic from d_walk() from dcache.c and simplify it for the mount case of tracefs if gid is set. All the files in tracefs will be walked and their group will be set to the value passed in. Link: https://lkml.kernel.org/r/20211207171729.2a54e1b3@gandalf.local.home Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reported-by: Kalesh Singh <kaleshsingh@google.com> Reported-by: Yabin Cui <yabinc@google.com> Fixes: 49d67e445742 ("tracefs: Have tracefs directories not set OTH permission bits by default") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-12-08tracefs: Have new files inherit the ownership of their parentSteven Rostedt (VMware)
If directories in tracefs have their ownership changed, then any new files and directories that are created under those directories should inherit the ownership of the director they are created in. Link: https://lkml.kernel.org/r/20211208075720.4855d180@gandalf.local.home Cc: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Yabin Cui <yabinc@google.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: stable@vger.kernel.org Fixes: 4282d60689d4f ("tracefs: Add new tracefs file system") Reported-by: Kalesh Singh <kaleshsingh@google.com> Reported: https://lore.kernel.org/all/CAC_TJve8MMAv+H_NdLSJXZUSoxOEq2zB_pVaJ9p=7H6Bu3X76g@mail.gmail.com/ Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-08tracefs: Have tracefs directories not set OTH permission bits by defaultSteven Rostedt (VMware)
The tracefs file system is by default mounted such that only root user can access it. But there are legitimate reasons to create a group and allow those added to the group to have access to tracing. By changing the permissions of the tracefs mount point to allow access, it will allow group access to the tracefs directory. There should not be any real reason to allow all access to the tracefs directory as it contains sensitive information. Have the default permission of directories being created not have any OTH (other) bits set, such that an admin that wants to give permission to a group has to first disable all OTH bits in the file system. Link: https://lkml.kernel.org/r/20210818153038.664127804@goodmis.org Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-03-23tracing: Fix various typos in commentsIngo Molnar
Fix ~59 single-word typos in the tracing code comments, and fix the grammar in a handful of places. Link: https://lore.kernel.org/r/20210322224546.GA1981273@gmail.com Link: https://lkml.kernel.org/r/20210323174935.GA4176821@gmail.com Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-01-24fs: make helpers idmap mount awareChristian Brauner
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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>
2019-10-12tracing: Do not create tracefs files if tracefs lockdown is in effectSteven Rostedt (VMware)
If on boot up, lockdown is activated for tracefs, don't even bother creating the files. This can also prevent instances from being created if lockdown is in effect. Link: http://lkml.kernel.org/r/CAHk-=whC6Ji=fWnjh2+eS4b15TnbsS4VPVtvBOwCy1jjEG_JHQ@mail.gmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-10-12tracefs: Revert ccbd54ff54e8 ("tracefs: Restrict tracefs when the kernel is ↵Steven Rostedt (VMware)
locked down") Running the latest kernel through my "make instances" stress tests, I triggered the following bug (with KASAN and kmemleak enabled): mkdir invoked oom-killer: gfp_mask=0x40cd0(GFP_KERNEL|__GFP_COMP|__GFP_RECLAIMABLE), order=0, oom_score_adj=0 CPU: 1 PID: 2229 Comm: mkdir Not tainted 5.4.0-rc2-test #325 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 Call Trace: dump_stack+0x64/0x8c dump_header+0x43/0x3b7 ? trace_hardirqs_on+0x48/0x4a oom_kill_process+0x68/0x2d5 out_of_memory+0x2aa/0x2d0 __alloc_pages_nodemask+0x96d/0xb67 __alloc_pages_node+0x19/0x1e alloc_slab_page+0x17/0x45 new_slab+0xd0/0x234 ___slab_alloc.constprop.86+0x18f/0x336 ? alloc_inode+0x2c/0x74 ? irq_trace+0x12/0x1e ? tracer_hardirqs_off+0x1d/0xd7 ? __slab_alloc.constprop.85+0x21/0x53 __slab_alloc.constprop.85+0x31/0x53 ? __slab_alloc.constprop.85+0x31/0x53 ? alloc_inode+0x2c/0x74 kmem_cache_alloc+0x50/0x179 ? alloc_inode+0x2c/0x74 alloc_inode+0x2c/0x74 new_inode_pseudo+0xf/0x48 new_inode+0x15/0x25 tracefs_get_inode+0x23/0x7c ? lookup_one_len+0x54/0x6c tracefs_create_file+0x53/0x11d trace_create_file+0x15/0x33 event_create_dir+0x2a3/0x34b __trace_add_new_event+0x1c/0x26 event_trace_add_tracer+0x56/0x86 trace_array_create+0x13e/0x1e1 instance_mkdir+0x8/0x17 tracefs_syscall_mkdir+0x39/0x50 ? get_dname+0x31/0x31 vfs_mkdir+0x78/0xa3 do_mkdirat+0x71/0xb0 sys_mkdir+0x19/0x1b do_fast_syscall_32+0xb0/0xed I bisected this down to the addition of the proxy_ops into tracefs for lockdown. It appears that the allocation of the proxy_ops and then freeing it in the destroy_inode callback, is causing havoc with the memory system. Reading the documentation about destroy_inode and talking with Linus about this, this is buggy and wrong. When defining the destroy_inode() method, it is expected that the destroy_inode() will also free the inode, and not just the extra allocations done in the creation of the inode. The faulty commit causes a memory leak of the inode data structure when they are deleted. Instead of allocating the proxy_ops (and then having to free it) the checks should be done by the open functions themselves, and not hack into the tracefs directory. First revert the tracefs updates for locked_down and then later we can add the locked_down checks in the kernel/trace files. Link: http://lkml.kernel.org/r/20191011135458.7399da44@gandalf.local.home Fixes: ccbd54ff54e8 ("tracefs: Restrict tracefs when the kernel is locked down") Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-09-28Merge branch 'next-lockdown' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull kernel lockdown mode from James Morris: "This is the latest iteration of the kernel lockdown patchset, from Matthew Garrett, David Howells and others. From the original description: This patchset introduces an optional kernel lockdown feature, intended to strengthen the boundary between UID 0 and the kernel. When enabled, various pieces of kernel functionality are restricted. Applications that rely on low-level access to either hardware or the kernel may cease working as a result - therefore this should not be enabled without appropriate evaluation beforehand. The majority of mainstream distributions have been carrying variants of this patchset for many years now, so there's value in providing a doesn't meet every distribution requirement, but gets us much closer to not requiring external patches. There are two major changes since this was last proposed for mainline: - Separating lockdown from EFI secure boot. Background discussion is covered here: https://lwn.net/Articles/751061/ - Implementation as an LSM, with a default stackable lockdown LSM module. This allows the lockdown feature to be policy-driven, rather than encoding an implicit policy within the mechanism. The new locked_down LSM hook is provided to allow LSMs to make a policy decision around whether kernel functionality that would allow tampering with or examining the runtime state of the kernel should be permitted. The included lockdown LSM provides an implementation with a simple policy intended for general purpose use. This policy provides a coarse level of granularity, controllable via the kernel command line: lockdown={integrity|confidentiality} Enable the kernel lockdown feature. If set to integrity, kernel features that allow userland to modify the running kernel are disabled. If set to confidentiality, kernel features that allow userland to extract confidential information from the kernel are also disabled. This may also be controlled via /sys/kernel/security/lockdown and overriden by kernel configuration. New or existing LSMs may implement finer-grained controls of the lockdown features. Refer to the lockdown_reason documentation in include/linux/security.h for details. The lockdown feature has had signficant design feedback and review across many subsystems. This code has been in linux-next for some weeks, with a few fixes applied along the way. Stephen Rothwell noted that commit 9d1f8be5cf42 ("bpf: Restrict bpf when kernel lockdown is in confidentiality mode") is missing a Signed-off-by from its author. Matthew responded that he is providing this under category (c) of the DCO" * 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (31 commits) kexec: Fix file verification on S390 security: constify some arrays in lockdown LSM lockdown: Print current->comm in restriction messages efi: Restrict efivar_ssdt_load when the kernel is locked down tracefs: Restrict tracefs when the kernel is locked down debugfs: Restrict debugfs when the kernel is locked down kexec: Allow kexec_file() with appropriate IMA policy when locked down lockdown: Lock down perf when in confidentiality mode bpf: Restrict bpf when kernel lockdown is in confidentiality mode lockdown: Lock down tracing and perf kprobes when in confidentiality mode lockdown: Lock down /proc/kcore x86/mmiotrace: Lock down the testmmiotrace module lockdown: Lock down module params that specify hardware parameters (eg. ioport) lockdown: Lock down TIOCSSERIAL lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down acpi: Disable ACPI table override if the kernel is locked down acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down ACPI: Limit access to custom_method when the kernel is locked down x86/msr: Restrict MSR access when the kernel is locked down x86: Lock down IO port access when the kernel is locked down ...
2019-08-19tracefs: Restrict tracefs when the kernel is locked downMatthew Garrett
Tracefs may release more information about the kernel than desirable, so restrict it when the kernel is locked down in confidentiality mode by preventing open(). (Fixed by Ben Hutchings to avoid a null dereference in default_file_open()) Signed-off-by: Matthew Garrett <mjg59@google.com> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
2019-07-10Merge tag 'fsnotify_for_v5.3-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull fsnotify updates from Jan Kara: "This contains cleanups of the fsnotify name removal hook and also a patch to disable fanotify permission events for 'proc' filesystem" * tag 'fsnotify_for_v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: fsnotify: get rid of fsnotify_nameremove() fsnotify: move fsnotify_nameremove() hook out of d_delete() configfs: call fsnotify_rmdir() hook debugfs: call fsnotify_{unlink,rmdir}() hooks debugfs: simplify __debugfs_remove_file() devpts: call fsnotify_unlink() hook tracefs: call fsnotify_{unlink,rmdir}() hooks rpc_pipefs: call fsnotify_{unlink,rmdir}() hooks btrfs: call fsnotify_rmdir() hook fsnotify: add empty fsnotify_{unlink,rmdir}() hooks fanotify: Disallow permission events for proc filesystem
2019-06-20tracefs: call fsnotify_{unlink,rmdir}() hooksAmir Goldstein
This will allow generating fsnotify delete events after the fsnotify_nameremove() hook is removed from d_delete(). Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-31tracefs: Annotate tracefs_ops with __ro_after_initZubin Mithra
tracefs_ops is initialized inside tracefs_create_instance_dir and not modified after. tracefs_create_instance_dir allows for initialization only once, and is called from create_trace_instances(marked __init), which is called from tracer_init_tracefs(marked __init). Also, mark tracefs_create_instance_dir as __init. Link: http://lkml.kernel.org/r/20180725171901.4468-1-zsm@chromium.org Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Zubin Mithra <zsm@chromium.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-07-06VFS: Don't use save/replace_mount_options if not using generic_show_optionsDavid Howells
btrfs, debugfs, reiserfs and tracefs call save_mount_options() and reiserfs calls replace_mount_options(), but they then implement their own ->show_options() methods and don't touch s_options, rendering the saved options unnecessary. I'm trying to eliminate s_options to make it easier to implement a context-based mount where the mount options can be passed individually over a file descriptor. Remove the calls to save/replace_mount_options() call in these cases. Signed-off-by: David Howells <dhowells@redhat.com> cc: Chris Mason <clm@fb.com> cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> cc: Steven Rostedt <rostedt@goodmis.org> cc: linux-btrfs@vger.kernel.org cc: reiserfs-devel@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-26fs: constify tree_descr arrays passed to simple_fill_super()Eric Biggers
simple_fill_super() is passed an array of tree_descr structures which describe the files to create in the filesystem's root directory. Since these arrays are never modified intentionally, they should be 'const' so that they are placed in .rodata and benefit from memory protection. This patch updates the function signature and all users, and also constifies tree_descr.name. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-09-27fs: Replace CURRENT_TIME with current_time() for inode timestampsDeepa Dinamani
CURRENT_TIME macro is not appropriate for filesystems as it doesn't use the right granularity for filesystem timestamps. Use current_time() instead. CURRENT_TIME is also not y2038 safe. This is also in preparation for the patch that transitions vfs timestamps to use 64 bit time and hence make them y2038 safe. As part of the effort current_time() will be extended to do range checks. Hence, it is necessary for all file system timestamps to use current_time(). Also, current_time() will be transitioned along with vfs to be y2038 safe. Note that whenever a single call to current_time() is used to change timestamps in different inodes, it is because they share the same time granularity. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Felipe Balbi <balbi@kernel.org> Acked-by: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Acked-by: David Sterba <dsterba@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-29tracefs: ->d_parent is never NULL or negative...Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-22wrappers for ->i_mutex accessAl Viro
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-04tracefs: Fix refcount imbalance in start_creating()Daniel Borkmann
In tracefs' start_creating(), we pin the file system to safely access its root. When we failed to create a file, we unpin the file system via failed_creating() to release the mount count and eventually the reference of the singleton vfsmount. However, when we run into an error during lookup_one_len() when still in start_creating(), we only release the parent's mutex but not so the reference on the mount. F.e., in securityfs_create_file(), after doing simple_pin_fs() when lookup_one_len() fails there, we infact do simple_release_fs(). This seems necessary here as well. Same issue seen in debugfs due to 190afd81e4a5 ("debugfs: split the beginning and the end of __create_file() off"), which seemed to got carried over into tracefs, too. Noticed during code review. Link: http://lkml.kernel.org/r/68efa86101b778cf7517ed7c6ad573bd69f60ec6.1446672850.git.daniel@iogearbox.net Fixes: 4282d60689d4 ("tracefs: Add new tracefs file system") Cc: stable@vger.kernel.org # 4.1+ Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-07-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
2015-07-01sysfs: Create mountpoints with sysfs_create_mount_pointEric W. Biederman
This allows for better documentation in the code and it allows for a simpler and fully correct version of fs_fully_visible to be written. The mount points converted and their filesystems are: /sys/hypervisor/s390/ s390_hypfs /sys/kernel/config/ configfs /sys/kernel/debug/ debugfs /sys/firmware/efi/efivars/ efivarfs /sys/fs/fuse/connections/ fusectl /sys/fs/pstore/ pstore /sys/kernel/tracing/ tracefs /sys/fs/cgroup/ cgroup /sys/kernel/security/ securityfs /sys/fs/selinux/ selinuxfs /sys/fs/smackfs/ smackfs Cc: stable@vger.kernel.org Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2015-06-23make simple_positive() publicAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-02-03tracing: Have mkdir and rmdir be part of tracefsSteven Rostedt (Red Hat)
The tracing "instances" directory can create sub tracing buffers with mkdir, and remove them with rmdir. As a mkdir will also create all the files and directories that control the sub buffer the inode mutexes need to be released before this is done, to avoid deadlocks. It is better to let the tracing system unlock the inode mutexes before calling the functions that create the files within the new directory (or deletes the files from the one being destroyed). Now that tracing has been converted over to tracefs, the tracefs file system can be modified to accommodate this feature. It still releases the locks, but the filesystem itself can take care of the ugly business and let the user just do what it needs. The tracing system now attaches a descriptor to the directory dentry that can have userspace create or remove sub directories. If this descriptor does not exist for a dentry, then that dentry can not be used to create other directories. This descriptor holds a mkdir and rmdir method that only takes a character string as an argument. The tracefs file system will first make a copy of the dentry name before releasing the locks. Then it will pass the copied name to the methods. It is up to the tracing system that supplied the methods to handle races with duplicate names and such as all the inode mutexes would be released when the functions are called. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-03tracefs: Add directory /sys/kernel/tracingSteven Rostedt (Red Hat)
When tracefs is configured, have the directory /sys/kernel/tracing appear just like /sys/kernel/debug appears when debugfs is configured. This will give a consistent place for system admins to mount tracefs. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-03tracefs: Add new tracefs file systemSteven Rostedt (Red Hat)
Add a separate file system to handle the tracing directory. Currently it is part of debugfs, but that is starting to show its limits. One thing is that in order to access the tracing infrastructure, you need to mount debugfs. As that includes debugging from all sorts of sub systems in the kernel, it is not considered advisable to mount such an all encompassing debugging system. Having the tracing system in its own file systems gives access to the tracing sub system without needing to include all other systems. Another problem with tracing using the debugfs system is that the instances use mkdir to create sub buffers. debugfs does not support mkdir from userspace so to implement it, special hacks were used. By controlling the file system that the tracing infrastructure uses, this can be properly done without hacks. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>