user/sven/linux.git/kernel, branch v4.14.281

perf: Fix sys_perf_event_open() race against self

2022-05-25T06:41:19Z

commit 3ac6487e584a1eb54071dbe1212e05b884136704 upstream. Norbert reported that it's possible to race sys_perf_event_open() such that the looser ends up in another context from the group leader, triggering many WARNs. The move_group case checks for races against itself, but the !move_group case doesn't, seemingly relying on the previous group_leader->ctx == ctx check. However, that check is racy due to not holding any locks at that time. Therefore, re-check the result after acquiring locks and bailing if they no longer match. Additionally, clarify the not_move_group case from the move_group-vs-move_group race. Fixes: f63a8daa5812 ("perf: Fix event->ctx locking") Reported-by: Norbert Slusarek Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp()

2022-05-18T07:18:08Z

commit 2685027fca387b602ae565bff17895188b803988 upstream. There are 3 places where the cpu and node masks of the top cpuset can be initialized in the order they are executed: 1) start_kernel -> cpuset_init() 2) start_kernel -> cgroup_init() -> cpuset_bind() 3) kernel_init_freeable() -> do_basic_setup() -> cpuset_init_smp() The first cpuset_init() call just sets all the bits in the masks. The second cpuset_bind() call sets cpus_allowed and mems_allowed to the default v2 values. The third cpuset_init_smp() call sets them back to v1 values. For systems with cgroup v2 setup, cpuset_bind() is called once. As a result, cpu and memory node hot add may fail to update the cpu and node masks of the top cpuset to include the newly added cpu or node in a cgroup v2 environment. For systems with cgroup v1 setup, cpuset_bind() is called again by rebind_subsystem() when the v1 cpuset filesystem is mounted as shown in the dmesg log below with an instrumented kernel. [ 2.609781] cpuset_bind() called - v2 = 1 [ 3.079473] cpuset_init_smp() called [ 7.103710] cpuset_bind() called - v2 = 0 smp_init() is called after the first two init functions. So we don't have a complete list of active cpus and memory nodes until later in cpuset_init_smp() which is the right time to set up effective_cpus and effective_mems. To fix this cgroup v2 mask setup problem, the potentially incorrect cpus_allowed & mems_allowed setting in cpuset_init_smp() are removed. For cgroup v2 systems, the initial cpuset_bind() call will set the masks correctly. For cgroup v1 systems, the second call to cpuset_bind() will do the right setup. cc: stable@vger.kernel.org Signed-off-by: Waiman Long Tested-by: Feng Tang Reviewed-by: Michal Koutný Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

tracing: Dump stacktrace trigger to the corresponding instance

2022-04-27T11:15:29Z

commit ce33c845b030c9cf768370c951bc699470b09fa7 upstream. The stacktrace event trigger is not dumping the stacktrace to the instance where it was enabled, but to the global "instance." Use the private_data, pointing to the trigger file, to figure out the corresponding trace instance, and use it in the trigger action, like snapshot_trigger does. Link: https://lkml.kernel.org/r/afbb0b4f18ba92c276865bc97204d438473f4ebc.1645396236.git.bristot@kernel.org Cc: stable@vger.kernel.org Fixes: ae63b31e4d0e2 ("tracing: Separate out trace events from global variables") Reviewed-by: Tom Zanussi Tested-by: Tom Zanussi Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman

tracing: Have traceon and traceoff trigger honor the instance

2022-04-27T11:15:29Z

commit 302e9edd54985f584cfc180098f3554774126969 upstream. If a trigger is set on an event to disable or enable tracing within an instance, then tracing should be disabled or enabled in the instance and not at the top level, which is confusing to users. Link: https://lkml.kernel.org/r/20220223223837.14f94ec3@rorschach.local.home Cc: stable@vger.kernel.org Fixes: ae63b31e4d0e2 ("tracing: Separate out trace events from global variables") Tested-by: Daniel Bristot de Oliveira Reviewed-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman

smp: Fix offline cpu check in flush_smp_call_function_queue()

2022-04-20T07:08:33Z

commit 9e949a3886356fe9112c6f6f34a6e23d1d35407f upstream. The check in flush_smp_call_function_queue() for callbacks that are sent to offline CPUs currently checks whether the queue is empty. However, flush_smp_call_function_queue() has just deleted all the callbacks from the queue and moved all the entries into a local list. This checks would only be positive if some callbacks were added in the short time after llist_del_all() was called. This does not seem to be the intention of this check. Change the check to look at the local list to which the entries were moved instead of the queue from which all the callbacks were just removed. Fixes: 8d056c48e4862 ("CPU hotplug, smp: flush any pending IPI callbacks before CPU offline") Signed-off-by: Nadav Amit Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20220319072015.1495036-1-namit@vmware.com Signed-off-by: Greg Kroah-Hartman

cgroup: Use open-time cgroup namespace for process migration perm checks

2022-04-20T07:08:30Z

commit e57457641613fef0d147ede8bd6a3047df588b95 upstream. cgroup process migration permission checks are performed at write time as whether a given operation is allowed or not is dependent on the content of the write - the PID. This currently uses current's cgroup namespace which is a potential security weakness as it may allow scenarios where a less privileged process tricks a more privileged one into writing into a fd that it created. This patch makes cgroup remember the cgroup namespace at the time of open and uses it for migration permission checks instad of current's. Note that this only applies to cgroup2 as cgroup1 doesn't have namespace support. This also fixes a use-after-free bug on cgroupns reported in https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Note that backporting this fix also requires the preceding patch. Reported-by: "Eric W. Biederman" Suggested-by: Linus Torvalds Cc: Michal Koutný Cc: Oleg Nesterov Reviewed-by: Michal Koutný Reported-by: syzbot+50f5cf33a284ce738b62@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Fixes: 5136f6365ce3 ("cgroup: implement "nsdelegate" mount option") Signed-off-by: Tejun Heo [mkoutny: v5.10: duplicate ns check in procs/threads write handler, adjust context] Signed-off-by: Michal Koutný Signed-off-by: Greg Kroah-Hartman [OP: backport to v4.14: drop changes to cgroup_attach_permissions() and cgroup_css_set_fork(), adjust cgroup_procs_write_permission() calls] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

cgroup: Allocate cgroup_file_ctx for kernfs_open_file->priv

2022-04-20T07:08:30Z

commit 0d2b5955b36250a9428c832664f2079cbf723bec upstream. of->priv is currently used by each interface file implementation to store private information. This patch collects the current two private data usages into struct cgroup_file_ctx which is allocated and freed by the common path. This allows generic private data which applies to multiple files, which will be used to in the following patch. Note that cgroup_procs iterator is now embedded as procs.iter in the new cgroup_file_ctx so that it doesn't need to be allocated and freed separately. v2: union dropped from cgroup_file_ctx and the procs iterator is embedded in cgroup_file_ctx as suggested by Linus. v3: Michal pointed out that cgroup1's procs pidlist uses of->priv too. Converted. Didn't change to embedded allocation as cgroup1 pidlists get stored for caching. Signed-off-by: Tejun Heo Cc: Linus Torvalds Reviewed-by: Michal Koutný [mkoutny: v5.10: modify cgroup.pressure handlers, adjust context] Signed-off-by: Michal Koutný Signed-off-by: Greg Kroah-Hartman [OP: backport to v4.14: drop changes to cgroup_pressure_*() functions] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

cgroup: Use open-time credentials for process migraton perm checks

2022-04-20T07:08:30Z

commit 1756d7994ad85c2479af6ae5a9750b92324685af upstream. cgroup process migration permission checks are performed at write time as whether a given operation is allowed or not is dependent on the content of the write - the PID. This currently uses current's credentials which is a potential security weakness as it may allow scenarios where a less privileged process tricks a more privileged one into writing into a fd that it created. This patch makes both cgroup2 and cgroup1 process migration interfaces to use the credentials saved at the time of open (file->f_cred) instead of current's. Reported-by: "Eric W. Biederman" Suggested-by: Linus Torvalds Fixes: 187fe84067bd ("cgroup: require write perm on common ancestor when moving processes on the default hierarchy") Reviewed-by: Michal Koutný Signed-off-by: Tejun Heo [OP: backport to v4.14: apply original __cgroup_procs_write() changes to cgroup_threads_write() and cgroup_procs_write()] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

printk: fix return value of printk.devkmsg __setup handler

2022-04-20T07:08:15Z

[ Upstream commit b665eae7a788c5e2bc10f9ac3c0137aa0ad1fc97 ] If an invalid option value is used with "printk.devkmsg=", it is silently ignored. If a valid option value is used, it is honored but the wrong return value (0) is used, indicating that the command line option had an error and was not handled. This string is not added to init's environment strings due to init/main.c::unknown_bootoption() checking for a '.' in the boot option string and then considering that string to be an "Unused module parameter". Print a warning message if a bad option string is used. Always return 1 from the __setup handler to indicate that the command line option has been handled. Fixes: 750afe7babd1 ("printk: add kernel parameter to control writes to /dev/kmsg") Signed-off-by: Randy Dunlap Reported-by: Igor Zhbanov Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Cc: Borislav Petkov Cc: Andrew Morton Cc: Petr Mladek Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: John Ogness Reviewed-by: John Ogness Reviewed-by: Sergey Senozhatsky Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20220228220556.23484-1-rdunlap@infradead.org Signed-off-by: Sasha Levin

perf/core: Fix address filter parser for multiple filters

2022-04-20T07:08:14Z

[ Upstream commit d680ff24e9e14444c63945b43a37ede7cd6958f9 ] Reset appropriate variables in the parser loop between parsing separate filters, so that they do not interfere with parsing the next filter. Fixes: 375637bc524952 ("perf/core: Introduce address range filtering") Signed-off-by: Adrian Hunter Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220131072453.2839535-4-adrian.hunter@intel.com Signed-off-by: Sasha Levin