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* PM: convert printk to pr_* equivalentMichal Hocko2019-05-021-16/+17
| | | | | | | | | | | | | | | | | While touching this area let's convert printk to pr_*. This also makes the printing of continuation lines done properly. Change-Id: Ib9408d407fc46960e42db5b67408494726f156a4 Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Moyster <oysterized@gmail.com>
* PM / freezer: Clean up code after recent fixesRafael J. Wysocki2019-05-021-15/+16
| | | | | | | | Clean up the code in process.c after recent changes to get rid of unnecessary labels and goto statements. Change-Id: I21245b4d20c44e957d9b61a2db6ac045bd21bad9 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PM / sleep: Mechanism for aborting system suspends unconditionallyRafael J. Wysocki2019-05-023-1/+21
| | | | | | | | | | | | | It sometimes may be necessary to abort a system suspend in progress or wake up the system from suspend-to-idle even if the pm_wakeup_event()/pm_stay_awake() mechanism is not enabled. For this purpose, introduce a new global variable pm_abort_suspend and make pm_wakeup_pending() check its value. Also add routines for manipulating that variable. Change-Id: I694bee866a1b9e85a724f3efec09326d47a4ef6e Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* sched_show_task: fix unsafe usage of ->real_parentOleg Nesterov2019-05-021-1/+3
| | | | | | | | | | | | | | | | | | | | rcu_read_lock() can not protect p->real_parent if release_task(p) was already called, change sched_show_task() to check pis_alive() like other users do. Note: we need some helpers to cleanup the code like this. And it seems that that the usage of cpu_curr(cpu) in dump_cpu_task() is not safe too. Change-Id: Id0b9f6dca6181fc9e406f003b3a652f27ae9109b Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched/core: Rework TASK_DEAD preemption exceptionPeter Zijlstra2019-05-021-6/+12
| | | | | | | | | | | | | | | | | | | | | | TASK_DEAD is special in that the final schedule call from do_exit() must be done with preemption disabled. This means we end up scheduling with a preempt_count() higher than usual (3 instead of the 'expected' 2). Since future patches will want to rely on an invariant preempt_count() value during schedule, fix this up. Change-Id: Icd3a40be4171553bb2d71fd7a82b6fac55218a12 Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/core: Fix TASK_DEAD race in finish_task_switch()Peter Zijlstra2019-05-022-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | So the problem this patch is trying to address is as follows: CPU0 CPU1 context_switch(A, B) ttwu(A) LOCK A->pi_lock A->on_cpu == 0 finish_task_switch(A) prev_state = A->state <-. WMB | A->on_cpu = 0; | UNLOCK rq0->lock | | context_switch(C, A) `-- A->state = TASK_DEAD prev_state == TASK_DEAD put_task_struct(A) context_switch(A, C) finish_task_switch(A) A->state == TASK_DEAD put_task_struct(A) The argument being that the WMB will allow the load of A->state on CPU0 to cross over and observe CPU1's store of A->state, which will then result in a double-drop and use-after-free. Now the comment states (and this was true once upon a long time ago) that we need to observe A->state while holding rq->lock because that will order us against the wakeup; however the wakeup will not in fact acquire (that) rq->lock; it takes A->pi_lock these days. We can obviously fix this by upgrading the WMB to an MB, but that is expensive, so we'd rather avoid that. The alternative this patch takes is: smp_store_release(&A->on_cpu, 0), which avoids the MB on some archs, but not important ones like ARM. Change-Id: Ie5c88d09e9a8c7b43fa0facbd24c10fc94245c93 Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> # v3.1+ Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: manfred@colorfullife.com Cc: will.deacon@arm.com Fixes: e4a52bcb9a18 ("sched: Remove rq->lock from the first half of ttwu()") Link: http://lkml.kernel.org/r/20150929124509.GG3816@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* kernel: exit: fix typo in commentFrans Klaver2019-05-021-1/+1
| | | | | | | | | | s,critiera,criteria, While at it, add a comma, because it makes sense grammatically. Change-Id: I055df466229e937564f28968605530b9dd0dbad5 Signed-off-by: Frans Klaver <fransklaver@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.com>
* exit,stats: /* obey this comment */Rik van Riel2019-05-021-1/+1
| | | | | | | | | | | | | | | | | There is a helpful comment in do_exit() that states we sync the mm's RSS info before statistics gathering. The function that does the statistics gathering is called right above that comment. Change the code to obey the comment. Change-Id: I6065ff9005dbd3e41730b66437db500520e8b70f Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: fix race between wait_consider_task() and wait_task_zombie()Oleg Nesterov2019-05-021-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | wait_consider_task() checks EXIT_ZOMBIE after EXIT_DEAD/EXIT_TRACE and both checks can fail if we race with EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE change in between, gcc needs to reload p->exit_state after security_task_wait(). In this case ->notask_error will be wrongly cleared and do_wait() can hang forever if it was the last eligible child. Many thanks to Arne who carefully investigated the problem. Note: this bug is very old but it was pure theoretical until commit b3ab03160dfa ("wait: completely ignore the EXIT_DEAD tasks"). Before this commit "-O2" was probably enough to guarantee that compiler won't read ->exit_state twice. Change-Id: I05a513b8340ae2e31ec3e0e0dc39ca17385d6121 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Arne Goedeke <el@laramies.com> Tested-by: Arne Goedeke <el@laramies.com> Cc: <stable@vger.kernel.org> [3.15+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: exit_notify: re-use "dead" list to autoreap currentOleg Nesterov2019-05-021-4/+2
| | | | | | | | | | | | | After the previous change we can add just the exiting EXIT_DEAD task to the "dead" list and remove another release_task(tsk). Change-Id: I6c3139d27d8ebaf78aec9bf4093f776e37336ccb Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: call forget_original_parent() under tasklist_lockOleg Nesterov2019-05-021-24/+23
| | | | | | | | | | | | | | | | | | | | | | Shift "release dead children" loop from forget_original_parent() to its caller, exit_notify(). It is safe to reap them even if our parent reaps us right after we drop tasklist_lock, those children no longer have any connection to the exiting task. And this allows us to avoid write_lock_irq(tasklist_lock) right after it was released by forget_original_parent(), we can simply call it with tasklist_lock held. While at it, move the comment about forget_original_parent() up to this function. Change-Id: I3a9a2880d44bdc3b828014187d3aee098f1ce860 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: avoid find_new_reaper() if no childrenOleg Nesterov2019-05-021-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that pid_ns logic was isolated we can change forget_original_parent() to return right after find_child_reaper() when father->children is empty, there is nothing to reparent in this case. In particular this avoids find_alive_thread() and this can help if the whole process exits and it has a lot of PF_EXITING threads at the start of the thread list, this can easily lead to O(nr_threads ** 2) iterations. Trivial test case (tested under KVM, 2 CPUs): static void *tfunc(void *arg) { pause(); return NULL; } static int child(unsigned int nt) { pthread_t pt; while (nt--) assert(pthread_create(&pt, NULL, tfunc, NULL) == 0); pthread_kill(pt, SIGTRAP); pause(); return 0; } int main(int argc, const char *argv[]) { int stat; unsigned int nf = atoi(argv[1]); unsigned int nt = atoi(argv[2]); while (nf--) { if (!fork()) return child(nt); wait(&stat); assert(stat == SIGTRAP); } return 0; } $ time ./test 16 16536 shows: real user sys - 5m37.628s 0m4.437s 8m5.560s + 0m50.032s 0m7.130s 1m4.927s Change-Id: Iacc713420ef4b81f0ab4e00da0c02ef233c78f45 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: introduce find_alive_thread()Oleg Nesterov2019-05-021-13/+19
| | | | | | | | | | | | | | | | | Add the new simple helper to factor out the for_each_thread() code in find_child_reaper() and find_new_reaper(). It can also simplify the potential PF_EXITING -> exit_state change, plus perhaps we can change this code to take SIGNAL_GROUP_EXIT into account. Change-Id: I76475039081a5ccc2d93a87b0674eee22447d773 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: introduce find_child_reaper()Oleg Nesterov2019-05-021-21/+35
| | | | | | | | | | | | | | | | | | | | find_new_reaper() does 2 completely different things. Not only it finds a reaper, it also updates pid_ns->child_reaper or kills the whole namespace if the caller is ->child_reaper. Now that has_child_subreaper logic doesn't depend on child_reaper check we can move that pid_ns code into a separate helper. IMHO this makes the code more clean, and this allows the next changes. Change-Id: I07e27342c622af10d3b8f0b71411839311943416 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: document the ->has_child_subreaper checksOleg Nesterov2019-05-021-8/+6
| | | | | | | | | | | | | | | | Swap the "init_task" and same_thread_group() checks. This way it is more simple to document these checks and we can remove the link to the previous discussion on lkml. Change-Id: Ie062e114468bb4922193d1e14265f49fb96f24ad Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: s/while_each_thread/for_each_thread/ in find_new_reaper()Oleg Nesterov2019-05-021-5/+3
| | | | | | | | | | | | | | | | | | | | | | Change find_new_reaper() to use for_each_thread() instead of deprecated while_each_thread(). We do not bother to check "thread != father" in the 1st loop, we can rely on PF_EXITING check. Note: this means the minor behavioural change: for_each_thread() starts from the group leader. But this should be fine, nobody should make any assumption about do_wait(__WNOTHREAD) when it comes to reparented tasks. And this can avoid the pointless reparenting to a short-living thread While zombie leaders are not that common. Change-Id: I877dc3563be39e17f0d02da3ed21e30763a0da9e Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: fix the cross-namespace PR_SET_CHILD_SUBREAPER reparentingOleg Nesterov2019-05-021-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | find_new_reaper() assumes that "has_child_subreaper" logic is safe as long as we are not the exiting ->child_reaper and this is doubly wrong: 1. In fact it is safe if "pid_ns->child_reaper == father"; there must be no children after zap_pid_ns_processes() returns, so it doesn't matter what we return in this case and even pid_ns->child_reaper is wrong otherwise: we can't reparent to ->child_reaper == current. This is not a bug, but this is confusing. 2. It is not safe if we are not pid_ns->child_reaper but from the same thread group. We drop tasklist_lock before zap_pid_ns_processes(), so another thread can lock it and choose the new reaper from the upper namespace if has_child_subreaper == T, and this is obviously wrong. This is not that bad, zap_pid_ns_processes() won't return until the the new reaper reaps all zombies, but this should be fixed anyway. We could change for_each_thread() loop to use ->exit_state instead of PF_EXITING which we had to use until 8aac62706ada, or we could change copy_signal() to check CLONE_NEWPID before setting has_child_subreaper, but lets change this code so that it is clear we can't look outside of our namespace, otherwise same_thread_group(reaper, child_reaper) check will look wrong and confusing anyway. We can simply start from "father" and fix the problem. We can't wrongly return a thread from the same thread group if ->is_child_subreaper == T, we know that all threads have PF_EXITING set. Change-Id: Iecba42469a52ff0a59feaa1b7a8c3d90a3886c85 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: fix the dead-parent PR_SET_CHILD_SUBREAPER reparentingOleg Nesterov2019-05-021-1/+1
| | | | | | | | | | | | | | | The ->has_child_subreaper code in find_new_reaper() finds alive "thread" but returns another "reaper" thread which can be dead. Change-Id: I3728d5741f0d5b10484fd745a0752d3908fc5b69 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: release_task: fix the comment about group leader accountingOleg Nesterov2019-05-021-7/+4
| | | | | | | | | | | | | | Contrary to what the comment in __exit_signal() says we do account the group leader. Fix this and explain why. Change-Id: Ib07c92c4debe3303eae43cabd1cd496ad5feda16 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: wait: drop tasklist_lock before psig->c* accountingOleg Nesterov2019-05-021-7/+5
| | | | | | | | | | | | | | wait_task_zombie() no longer needs tasklist_lock to accumulate the psig->c* counters, we can drop it right after cmpxchg(exit_state). Change-Id: I7cc68ac84ce681c95c0a532454ba79ffa6fc35a9 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: wait: cleanup the ptrace_reparented() checksOleg Nesterov2019-05-021-8/+6
| | | | | | | | | | | | | | | | | | | | | Now that EXIT_DEAD is the terminal state we can kill "int traced" variable and check "state == EXIT_DEAD" instead to cleanup the code. In particular, this way it is clear that the check obviously doesn't need tasklist_lock. Also fix the type of "unsigned long state", "long" was always wrong although this doesn't matter because cmpxchg/xchg uses typeof(*ptr). [akpm@linux-foundation.org: don't make me google the C Operator Precedence table] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Change-Id: Ib88f1ca951ef8e1ab2c34cf8f199a5775c9b22b1
* exit: ptrace: shift "reap dead" code from exit_ptrace() to ↵Oleg Nesterov2019-05-023-27/+8
| | | | | | | | | | | | | | | | | | | | | | | forget_original_parent() Now that forget_original_parent() uses ->ptrace_entry for EXIT_DEAD tasks, we can simply pass "dead_children" list to exit_ptrace() and remove another release_task() loop. Plus this way we do not need to drop and reacquire tasklist_lock. Also shift the list_empty(ptraced) check, if we want this optimization it makes sense to eliminate the function call altogether. Change-Id: I07b22f882fe7d5ec0bdc4f12d416992f96567610 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: cleanup the usage of reparent_leader()Oleg Nesterov2019-05-021-13/+9
| | | | | | | | | | | | | | | | | | | | | 1. Now that reparent_leader() doesn't abuse ->sibling we can shift list_move_tail() from reparent_leader() to forget_original_parent() and turn it into a single list_splice_tail_init(). This also makes BUG_ON(!list_empty()) and list_for_each_entry_safe() unnecessary. 2. This also allows to shift the same_thread_group() check, it looks a bit more clear in the caller. Change-Id: I0ff440bcbca0ff898d7e893b7778d5097d0542c7 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: reparent: cleanup the changing of ->parentOleg Nesterov2019-05-021-8/+5
| | | | | | | | | | | | | | | | | | | | | | | | | 1. Cosmetic, but "if (t->parent == father)" looks a bit confusing. We need to change t->parent if and only if t is not traced. 2. If we actually want this BUG_ON() to ensure that parent/ptrace match each other, then we should also take ptrace_reparented() case into account too. 3. Change this code to use for_each_thread() instead of deprecated while_each_thread(). [dan.carpenter@oracle.com: silence a bogus static checker warning] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Change-Id: If69ec59b8eef170a67088da1aecaf1fad92226cf
* exit: reparent: use ->ptrace_entry rather than ->sibling for EXIT_DEAD tasksOleg Nesterov2019-05-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | reparent_leader() reuses ->sibling as a list node to add an EXIT_DEAD task into dead_children list we are going to release. This obviously removes the dead task from its real_parent->children list and this is even good; the parent can do nothing with the EXIT_DEAD reparented zombie, it only makes do_wait() slower. But, this also means that it can not be reparented once again, so if its new parent dies too nobody will update ->parent/real_parent, they can point to the freed memory even before release_task() we are going to call, this breaks the code which relies on pid_alive() to access ->real_parent/parent. Fortunately this is mostly theoretical, this can only happen if init or PR_SET_CHILD_SUBREAPER process ignores SIGCHLD and the new parent sub-thread exits right after we drop tasklist_lock. Change this code to use ->ptrace_entry instead, we know that the child is not traced so nobody can ever use this member. This also allows to unify this logic with exit_ptrace(), see the next changes. Note: we really need to change release_task() to nullify real_parent/ parent/group_leader pointers, but we need to change the current users first somehow. And it would be better to reap this zombie immediately but release_task_locked() we need is complicated by proc_flush_task(). Change-Id: I81889ce9d296b5efa1afb47a9fa2f45d8ed1bb9a Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Cc: Sterling Alexander <stalexan@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roland McGrath <roland@hack.frob.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched, exit: Deal with nested sleepsPeter Zijlstra2019-05-022-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | do_wait() is a big wait loop, but we set TASK_RUNNING too late; we end up calling potential sleeps before we reset it. Not strictly a bug since we're guaranteed to exit the loop and not call schedule(); put in annotations to quiet might_sleep(). WARNING: CPU: 0 PID: 1 at ../kernel/sched/core.c:7123 __might_sleep+0x7e/0x90() do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8109a788>] do_wait+0x88/0x270 Call Trace: [<ffffffff81694991>] dump_stack+0x4e/0x7a [<ffffffff8109877c>] warn_slowpath_common+0x8c/0xc0 [<ffffffff8109886c>] warn_slowpath_fmt+0x4c/0x50 [<ffffffff810bca6e>] __might_sleep+0x7e/0x90 [<ffffffff811a1c15>] might_fault+0x55/0xb0 [<ffffffff8109a3fb>] wait_consider_task+0x90b/0xc10 [<ffffffff8109a804>] do_wait+0x104/0x270 [<ffffffff8109b837>] SyS_wait4+0x77/0x100 [<ffffffff8169d692>] system_call_fastpath+0x16/0x1b Change-Id: I6d0a7e2ac676fe95e27068518d1fe69108864fe9 Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: tglx@linutronix.de Cc: umgwanakikbuti@gmail.com Cc: ilya.dryomov@inktank.com Cc: Alex Elder <alex.elder@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Axel Lin <axel.lin@ingics.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Dave Jones <davej@redhat.com> Cc: Guillaume Morin <guillaume@morinfr.org> Cc: Ionut Alexa <ionut.m.alexa@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20140924082242.186408915@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* exit: Always reap resource stats in __exit_signal()Rik van Riel2019-05-021-22/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Oleg pointed out that wait_task_zombie adds a task's usage statistics to the parent's signal struct, but the task's own signal struct should also propagate the statistics at exit time. This allows thread_group_cputime(reaped_zombie) to get the statistics after __unhash_process() has made the task invisible to for_each_thread, but before the thread has actually been rcu freed, making sure no non-monotonic results are returned inside that window. Change-Id: I2a66eb570cecd344323e4f842fd89b22f4b6f001 Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Guillaume Morin <guillaume@morinfr.org> Cc: Ionut Alexa <ionut.m.alexa@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: umgwanakikbuti@gmail.com Cc: fweisbec@gmail.com Cc: srao@redhat.com Cc: lwoodman@redhat.com Cc: atheurer@redhat.com Link: http://lkml.kernel.org/r/1408133138-22048-2-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* kernel/exit.c: fix coding style warnings and errorsIonut Alexa2019-05-021-23/+26
| | | | | | | | | Fixed coding style warnings and errors. Change-Id: I8ec4e7959700a05aa082778812f38d70cecdf7ea Signed-off-by: Ionut Alexa <ionut.m.alexa@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, oom: remove unnecessary exit_state checkDavid Rientjes2019-05-022-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | The oom killer scans each process and determines whether it is eligible for oom kill or whether the oom killer should abort because of concurrent memory freeing. It will abort when an eligible process is found to have TIF_MEMDIE set, meaning it has already been oom killed and we're waiting for it to exit. Processes with task->mm == NULL should not be considered because they are either kthreads or have already detached their memory and killing them would not lead to memory freeing. That memory is only freed after exit_mm() has returned, however, and not when task->mm is first set to NULL. Clear TIF_MEMDIE after exit_mm()'s mmput() so that an oom killed process is no longer considered for oom kill, but only until exit_mm() has returned. This was fragile in the past because it relied on exit_notify() to be reached before no longer considering TIF_MEMDIE processes. Change-Id: I072465956d32c33a3d08975849a0adbe43ee4389 Signed-off-by: David Rientjes <rientjes@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: mv {dis,}allow_signal() from sched.h/exit.c to signal.[ch]Oleg Nesterov2019-05-024-42/+31
| | | | | | | | | | | | | | | | | | | | | | | | | Move the declaration/definition of allow_signal/disallow_signal to signal.h/signal.c. The new place is more logical and allows to use the static helpers in signal.c (see the next changes). While at it, make them return void and remove the valid_signal() check. Nobody checks the returned value, and in-kernel users must not pass the wrong signal number. Change-Id: I75a6d15eaa4a6c01175823f8d07c356869da9db2 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Richard Weinberger <richard@nod.at> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit.c: unexport __set_special_pids()Oleg Nesterov2019-05-023-14/+12
| | | | | | | | | | | | | | Move __set_special_pids() from exit.c to sys.c close to its single caller and make it static. And rename it to set_special_pids(), another helper with this name has gone away. Change-Id: I0095999c845fabe07cdb3854c5ee1866220e3198 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: WSTOPPED|WCONTINUED doesn't work if a zombie leader is traced by ↵Oleg Nesterov2019-05-021-13/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | another process Even if the main thread is dead the process still can stop/continue. However, if the leader is ptraced wait_consider_task(ptrace => false) always skips wait_task_stopped/wait_task_continued, so WSTOPPED or WCONTINUED can never work for the natural parent in this case. Move the "A zombie ptracee is only visible to its ptracer" check into the "if (!delay_group_leader(p))" block. ->notask_error is cleared by the "fall through" code below. This depends on the previous change, wait_task_stopped/continued must be avoided if !delay_group_leader() and the tracer is ->real_parent. Otherwise WSTOPPED|WEXITED could wrongly report "stopped" when the child is already dead (single-threaded or not). If it is traced by another task then the "stopped" state is fine until the debugger detaches and reveals a zombie state. Stupid test-case: void *tfunc(void *arg) { sleep(1); // wait for zombie leader raise(SIGSTOP); exit(0x13); return NULL; } int run_child(void) { pthread_t thread; if (!fork()) { int tracee = getppid(); assert(ptrace(PTRACE_ATTACH, tracee, 0,0) == 0); do ptrace(PTRACE_CONT, tracee, 0,0); while (wait(NULL) > 0); return 0; } sleep(1); // wait for PTRACE_ATTACH assert(pthread_create(&thread, NULL, tfunc, NULL) == 0); pthread_exit(NULL); } int main(void) { int child, stat; child = fork(); if (!child) return run_child(); assert(child == waitpid(-1, &stat, WSTOPPED)); assert(stat == 0x137f); kill(child, SIGCONT); assert(child == waitpid(-1, &stat, WCONTINUED)); assert(stat == 0xffff); assert(child == waitpid(-1, &stat, 0)); assert(stat == 0x1300); return 0; } Without this patch it hangs in waitpid(WSTOPPED), wait_task_stopped() is never called. Note: this doesn't fix all problems with a zombie delay_group_leader(), WCONTINUED | WEXITED check is not exactly right. debugger can't assume it will be notified if another thread reaps the whole thread group. Change-Id: Ie93b67984c30832e593d1aec21fd1645ab5eed56 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: WSTOPPED|WCONTINUED hangs if a zombie child is traced by real_parentOleg Nesterov2019-05-021-13/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "A zombie is only visible to its ptracer" logic in wait_consider_task() is very wrong. Trivial test-case: #include <unistd.h> #include <sys/ptrace.h> #include <sys/wait.h> #include <assert.h> int main(void) { int child = fork(); if (!child) { assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0); return 0x23; } assert(waitid(P_ALL, child, NULL, WEXITED | WNOWAIT) == 0); assert(waitid(P_ALL, 0, NULL, WSTOPPED) == -1); return 0; } it hangs in waitpid(WSTOPPED) despite the fact it has a single zombie child. This is because wait_consider_task(ptrace => 0) sees p->ptrace and cleares ->notask_error assuming that the debugger should detach and notify us. Change wait_consider_task(ptrace => 0) to pretend that ptrace == T if the child is traced by us. This really simplifies the logic and allows us to do more fixes, see the next changes. This also hides the unwanted group stop state automatically, we can remove another ptrace_reparented() check. Unfortunately, this adds the following behavioural changes: 1. Before this patch wait(WEXITED | __WNOTHREAD) does not reap a natural child if it is traced by the caller's sub-thread. Hopefully nobody will ever notice this change, and I think that nobody should rely on this behaviour anyway. 2. SIGNAL_STOP_CONTINUED is no longer hidden from debugger if it is real parent. While this change comes as a side effect, I think it is good by itself. The group continued state can not be consumed by another process in this case, it doesn't depend on ptrace, it doesn't make sense to hide it from real parent. Perhaps we should add the thread_group_leader() check before wait_task_continued()? May be, but this shouldn't depend on ptrace_reparented(). Change-Id: Iff1e0cd6f78c3c590f0f3f064096994c30bb59c1 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: completely ignore the EXIT_DEAD tasksOleg Nesterov2019-05-021-5/+6
| | | | | | | | | | | | | | | | Now that EXIT_DEAD is the terminal state it doesn't make sense to call eligible_child() or security_task_wait() if the task is really dead. Change-Id: I4bb64edf3b22a827899b059eaffd1b030e8c1e3e Signed-off-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: use EXIT_TRACE only if thread_group_leader(zombie)Oleg Nesterov2019-05-021-10/+7
| | | | | | | | | | | | | | | | | | | | | wait_task_zombie() always uses EXIT_TRACE/ptrace_unlink() if ptrace_reparented(). This is suboptimal and a bit confusing: we do not need do_notify_parent(p) if !thread_group_leader(p) and in this case we also do not need ptrace_unlink(), we can rely on ptrace_release_task(). Change wait_task_zombie() to check thread_group_leader() along with ptrace_reparented() and simplify the final p->exit_state transition. Change-Id: I4e5f79e0b8900b0b167f82c596ce5ad235745be6 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: introduce EXIT_TRACE to avoid the racy EXIT_DEAD->EXIT_ZOMBIE transitionOleg Nesterov2019-05-022-29/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wait_task_zombie() first does EXIT_ZOMBIE->EXIT_DEAD transition and drops tasklist_lock. If this task is not the natural child and it is traced, we change its state back to EXIT_ZOMBIE for ->real_parent. The last transition is racy, this is even documented in 50b8d257486a "ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race". wait_consider_task() tries to detect this transition and clear ->notask_error but we can't rely on ptrace_reparented(), debugger can exit and do ptrace_unlink() before its sub-thread sets EXIT_ZOMBIE. And there is another problem which were missed before: this transition can also race with reparent_leader() which doesn't reset >exit_signal if EXIT_DEAD, assuming that this task must be reaped by someone else. So the tracee can be re-parented with ->exit_signal != SIGCHLD, and if /sbin/init doesn't use __WALL it becomes unreapable. This was fixed by the previous commit, but it was the temporary hack. 1. Add the new exit_state, EXIT_TRACE. It means that the task is the traced zombie, debugger is going to detach and notify its natural parent. This new state is actually EXIT_ZOMBIE | EXIT_DEAD. This way we can avoid the changes in proc/kgdb code, get_task_state() still reports "X (dead)" in this case. Note: with or without this change userspace can see Z -> X -> Z transition. Not really bad, but probably makes sense to fix. 2. Change wait_task_zombie() to use EXIT_TRACE instead of EXIT_DEAD if we need to notify the ->real_parent. 3. Revert the previous hack in reparent_leader(), now that EXIT_DEAD is always the final state we can safely ignore such a task. 4. Change wait_consider_task() to check EXIT_TRACE separately and kill the racy and no longer needed ptrace_reparented() case. If ptrace == T an EXIT_TRACE thread should be simply ignored, the owner of this state is going to ptrace_unlink() this task. We can pretend that it was already removed from ->ptraced list. Otherwise we should skip this thread too but clear ->notask_error, we must be the natural parent and debugger is going to untrace and notify us. IOW, this doesn't differ from "EXIT_ZOMBIE && p->ptrace" even if the task was already untraced. Change-Id: I972c5bc91a93901ef836bf4f6a53af06f6a0a1e9 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com> Reported-by: Michal Schmidt <mschmidt@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/exit.c: call proc_exit_connector() after exit_state is setGuillaume Morin2019-05-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The process events connector delivers a notification when a process exits. This is really convenient for a process that spawns and wants to monitor its children through an epoll-able() interface. Unfortunately, there is a small window between when the event is delivered and the child become wait()-able. This is creates a race if the parent wants to make sure that it knows about the exit, e.g pid_t pid = fork(); if (pid > 0) { register_interest_for_pid(pid); if (waitpid(pid, NULL, WNOHANG) > 0) { /* We might have raced with exit() */ } return; } /* Child */ execve(...) register_interest_for_pid() would be telling the the connector socket reader to pay attention to events related to pid. Though this is not a bug, I think it would make the connector a bit more usable if this race was closed by simply moving the call to proc_exit_connector() from just before exit_notify() to right after. Oleg said: : Even with this patch the code above is still "racy" if the child is : multi-threaded. Plus it should obviously filter-out subthreads. And : afaics there is no way to make it reliable, even if you change the code : above so that waitpid() is called only after the last thread exits WNOHANG : still can fail. Change-Id: Iaf411e2e5123a1082d7c8c955689874f89aa877b Signed-off-by: Guillaume Morin <guillaume@morinfr.org> Cc: Matt Helsley <matt.helsley@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* exit: move check_stack_usage() to the end of do_exit()Oleg Nesterov2019-05-021-1/+1
| | | | | | | | | | | | | | It is not clear why check_stack_usage() is called so early and thus it never checks the stack usage in, say, exit_notify() or flush_ptrace_hw_breakpoint() or other functions which are only called by do_exit(). Move the callsite down to the last preempt_disable/schedule. Change-Id: I0146bdcc09af5cb6df1cbeec42c630fd6210d2d8 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: cleanup the usage of t/current in do_sigaction()Oleg Nesterov2019-05-021-8/+7
| | | | | | | | | | | | | | | | | | | | | | | | The usage of "task_struct *t" and "current" in do_sigaction() looks really annoying and chaotic. Initially "t" is used as a cached value of current but not consistently, then it is reused as a loop variable and we have to use "current" again. Clean up this mess and also convert the code to use for_each_thread(). Change-Id: Ibafe371d596e164661767b21d5550a1e0bd740ff Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Richard Weinberger <richard@nod.at> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: rename rm_from_queue_full() to flush_sigqueue_mask()Oleg Nesterov2019-05-021-11/+8
| | | | | | | | | | | | | | | | | | | | | | | | "rm_from_queue_full" looks ugly and misleading, especially now that rm_from_queue() has gone away. Rename it to flush_sigqueue_mask(), this matches flush_sigqueue() we already have. Also remove the obsolete comment which explains the difference with rm_from_queue() we already killed. Change-Id: Ieb09df78f3c415ad47f4afbaade6b7625783d579 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Richard Weinberger <richard@nod.at> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/signal.c: change do_signal_stop/do_sigaction to use while_each_thread()Oleg Nesterov2019-05-021-4/+3
| | | | | | | | | | | | | | Change do_signal_stop() and do_sigaction() to avoid next_thread() and use while_each_thread() instead. Change-Id: I6a34f65244048e113815d6e5afaaed2911a8d93d Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Reviewed-by: Sameer Nanda <snanda@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: kill rm_from_queue(), change prepare_signal() to use for_each_thread()Oleg Nesterov2019-05-021-33/+10
| | | | | | | | | | | | | | | | | | | | | | | rm_from_queue() doesn't make sense. The only caller, prepare_signal(), can use rm_from_queue_full() with the same effect. While at it, change prepare_signal() to use for_each_thread() instead of do/while_each_thread. Change-Id: I19d6987cb0dd4a066686f9edc72496eac4d58391 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Richard Weinberger <richard@nod.at> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lib/is_single_threaded.c: change current_is_single_threaded() to use ↵Oleg Nesterov2019-05-021-3/+2
| | | | | | | | | | | | | for_each_thread() Change current_is_single_threaded() to use for_each_thread() rather than deprecated while_each_thread(). Change-Id: Ie0abc34982554e4ec5e0d2a8457c9bbd386c814d Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* locking/lockdep: Use for_each_process_thread() for debug_show_all_locks()Tetsuo Handa2019-05-021-35/+8
| | | | | | | | | | | | | | | | | | | | | | | debug_show_all_locks() tries to grab the tasklist_lock for two seconds, but calling while_each_thread() without tasklist_lock held is not safe. See the following commit for more information: 4449a51a7c281602 ("vm_is_stack: use for_each_thread() rather then buggy while_each_thread()") Change debug_show_all_locks() from "do_each_thread()/while_each_thread() with possibility of missing tasklist_lock" to "for_each_process_thread() with RCU", and add a call to touch_all_softlockup_watchdogs() like show_state_filter() does. Change-Id: I502b9ea50d180aedad7f379ffc0b987d0223d739 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1523011279-8206-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Avoid triggering hardlockup from debug_show_all_locks()Tejun Heo2019-05-021-0/+2
| | | | | | | | | | | | | | | | | | | | debug_show_all_locks() iterates all tasks and print held locks whole holding tasklist_lock. This can take a while on a slow console device and may end up triggering NMI hardlockup detector if someone else ends up waiting for tasklist_lock. Touch the NMI watchdog while printing the held locks to avoid spuriously triggering the hardlockup detector. Change-Id: I8ed50849c4464de1e2936d75b945e568a6090561 Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-team@fb.com Link: http://lkml.kernel.org/r/20180122220055.GB1771050@devbig577.frc2.facebook.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* kernel/hung_task.c: change hung_task.c to use for_each_process_thread()Aaron Tomlin2019-05-021-2/+2
| | | | | | | | | | | | | | | | | | In check_hung_uninterruptible_tasks() avoid the use of deprecated while_each_thread(). The "max_count" logic will prevent a livelock - see commit 0c740d0a ("introduce for_each_thread() to replace the buggy while_each_thread()"). Having said this let's use for_each_process_thread(). Change-Id: I607d1819ab824d072f73363b1e429e2d0952b93d Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Wysochanski <dwysocha@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ALSA: pcm: Fix potential Spectre v1 vulnerabilityGustavo A. R. Silva2019-05-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | commit 94ffb030b6d31ec840bb811be455dd2e26a4f43e upstream. stream is indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: sound/core/pcm.c:140 snd_pcm_control_ioctl() warn: potential spectre issue 'pcm->streams' [r] (local cap) Fix this by sanitizing stream before using it to index pcm->streams Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Change-Id: I5fd73f88a116ada553b9f2495674fdc01be6b661 Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* ALSA: pcm: Don't suspend stream in unrecoverable PCM stateTakashi Iwai2019-05-021-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 113ce08109f8e3b091399e7cc32486df1cff48e7 upstream. Currently PCM core sets each opened stream forcibly to SUSPENDED state via snd_pcm_suspend_all() call, and the user-space is responsible for re-triggering the resume manually either via snd_pcm_resume() or prepare call. The scheme works fine usually, but there are corner cases where the stream can't be resumed by that call: the streams still in OPEN state before finishing hw_params. When they are suspended, user-space cannot perform resume or prepare because they haven't been set up yet. The only possible recovery is to re-open the device, which isn't nice at all. Similarly, when a stream is in DISCONNECTED state, it makes no sense to change it to SUSPENDED state. Ditto for in SETUP state; which you can re-prepare directly. So, this patch addresses these issues by filtering the PCM streams to be suspended by checking the PCM state. When a stream is in either OPEN, SETUP or DISCONNECTED as well as already SUSPENDED, the suspend action is skipped. To be noted, this problem was originally reported for the PCM runtime PM on HD-audio. And, the runtime PM problem itself was already addressed (although not intended) by the code refactoring commits 3d21ef0b49f8 ("ALSA: pcm: Suspend streams globally via device type PM ops") and 17bc4815de58 ("ALSA: pci: Remove superfluous snd_pcm_suspend*() calls"). These commits eliminated the snd_pcm_suspend*() calls from the runtime PM suspend callback code path, hence the racy OPEN state won't appear while runtime PM. (FWIW, the race window is between snd_pcm_open_substream() and the first power up in azx_pcm_open().) Although the runtime PM issue was already "fixed", the same problem is still present for the system PM, hence this patch is still needed. And for stable trees, this patch alone should suffice for fixing the runtime PM problem, too. Change-Id: I60531a00278ab5d4a04b04012417f53610b131db Reported-and-tested-by: Jon Hunter <jonathanh@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* vfs: delete vfs_readdir function declarationZhang Zhen2019-05-021-1/+0
| | | | | | | | | | | vfs_readdir() was replaced by iterate_dir() in commit 5c0ba4e0762e ("[readdir] introduce iterate_dir() and dir_context"). Change-Id: I0a04fe567a55afabb19a75dc944b4ef62c6cadb4 Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* convert codaAl Viro2019-05-021-58/+19
| | | | | Change-Id: I72ec99809512ad931238def3c9e789617c048b53 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
generated by cgit v1.2.3 (git 2.39.1) at 2026-03-17 02:58:54 +0000