* [PATCH v3 1/3] mm, oom: refactor dump_tasks for memcg OOMs @ 2019-06-24 21:26 Shakeel Butt 2019-06-24 21:26 ` [PATCH v3 2/3] mm, oom: remove redundant task_in_mem_cgroup() check Shakeel Butt 2019-06-24 21:26 ` [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task Shakeel Butt 0 siblings, 2 replies; 9+ messages in thread From: Shakeel Butt @ 2019-06-24 21:26 UTC (permalink / raw) To: Johannes Weiner, Vladimir Davydov, Michal Hocko, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, Nick Piggin Cc: linux-mm, linux-kernel, Shakeel Butt, Michal Hocko dump_tasks() traverses all the existing processes even for the memcg OOM context which is not only unnecessary but also wasteful. This imposes a long RCU critical section even from a contained context which can be quite disruptive. Change dump_tasks() to be aligned with select_bad_process and use mem_cgroup_scan_tasks to selectively traverse only processes of the target memcg hierarchy during memcg OOM. Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> --- Changelog since v2: - Updated the commit message. Changelog since v1: - Divide the patch into two patches. mm/oom_kill.c | 68 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 40 insertions(+), 28 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 05aaa1a5920b..bd80997e0969 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -385,10 +385,38 @@ static void select_bad_process(struct oom_control *oc) oc->chosen_points = oc->chosen_points * 1000 / oc->totalpages; } +static int dump_task(struct task_struct *p, void *arg) +{ + struct oom_control *oc = arg; + struct task_struct *task; + + if (oom_unkillable_task(p, NULL, oc->nodemask)) + return 0; + + task = find_lock_task_mm(p); + if (!task) { + /* + * This is a kthread or all of p's threads have already + * detached their mm's. There's no need to report + * them; they can't be oom killed anyway. + */ + return 0; + } + + pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n", + task->pid, from_kuid(&init_user_ns, task_uid(task)), + task->tgid, task->mm->total_vm, get_mm_rss(task->mm), + mm_pgtables_bytes(task->mm), + get_mm_counter(task->mm, MM_SWAPENTS), + task->signal->oom_score_adj, task->comm); + task_unlock(task); + + return 0; +} + /** * dump_tasks - dump current memory state of all system tasks - * @memcg: current's memory controller, if constrained - * @nodemask: nodemask passed to page allocator for mempolicy ooms + * @oc: pointer to struct oom_control * * Dumps the current memory state of all eligible tasks. Tasks not in the same * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes @@ -396,37 +424,21 @@ static void select_bad_process(struct oom_control *oc) * State information includes task's pid, uid, tgid, vm size, rss, * pgtables_bytes, swapents, oom_score_adj value, and name. */ -static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask) +static void dump_tasks(struct oom_control *oc) { - struct task_struct *p; - struct task_struct *task; - pr_info("Tasks state (memory values in pages):\n"); pr_info("[ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name\n"); - rcu_read_lock(); - for_each_process(p) { - if (oom_unkillable_task(p, memcg, nodemask)) - continue; - task = find_lock_task_mm(p); - if (!task) { - /* - * This is a kthread or all of p's threads have already - * detached their mm's. There's no need to report - * them; they can't be oom killed anyway. - */ - continue; - } + if (is_memcg_oom(oc)) + mem_cgroup_scan_tasks(oc->memcg, dump_task, oc); + else { + struct task_struct *p; - pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n", - task->pid, from_kuid(&init_user_ns, task_uid(task)), - task->tgid, task->mm->total_vm, get_mm_rss(task->mm), - mm_pgtables_bytes(task->mm), - get_mm_counter(task->mm, MM_SWAPENTS), - task->signal->oom_score_adj, task->comm); - task_unlock(task); + rcu_read_lock(); + for_each_process(p) + dump_task(p, oc); + rcu_read_unlock(); } - rcu_read_unlock(); } static void dump_oom_summary(struct oom_control *oc, struct task_struct *victim) @@ -458,7 +470,7 @@ static void dump_header(struct oom_control *oc, struct task_struct *p) dump_unreclaimable_slab(); } if (sysctl_oom_dump_tasks) - dump_tasks(oc->memcg, oc->nodemask); + dump_tasks(oc); if (p) dump_oom_summary(oc, p); } -- 2.22.0.410.gd8fdbe21b5-goog ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v3 2/3] mm, oom: remove redundant task_in_mem_cgroup() check 2019-06-24 21:26 [PATCH v3 1/3] mm, oom: refactor dump_tasks for memcg OOMs Shakeel Butt @ 2019-06-24 21:26 ` Shakeel Butt 2019-06-26 6:38 ` Michal Hocko 2019-06-24 21:26 ` [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task Shakeel Butt 1 sibling, 1 reply; 9+ messages in thread From: Shakeel Butt @ 2019-06-24 21:26 UTC (permalink / raw) To: Johannes Weiner, Vladimir Davydov, Michal Hocko, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, Nick Piggin Cc: linux-mm, linux-kernel, Shakeel Butt oom_unkillable_task() can be called from three different contexts i.e. global OOM, memcg OOM and oom_score procfs interface. At the moment oom_unkillable_task() does a task_in_mem_cgroup() check on the given process. Since there is no reason to perform task_in_mem_cgroup() check for global OOM and oom_score procfs interface, those contexts provide NULL memcg and skips the task_in_mem_cgroup() check. However for memcg OOM context, the oom_unkillable_task() is always called from mem_cgroup_scan_tasks() and thus task_in_mem_cgroup() check becomes redundant. So, just remove the task_in_mem_cgroup() check altogether. Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- Changelog since v2: - Further divided the patch into two patches. - Incorporated the task_in_mem_cgroup() from Tetsuo. Changelog since v1: - Divide the patch into two patches. fs/proc/base.c | 2 +- include/linux/memcontrol.h | 7 ------- include/linux/oom.h | 2 +- mm/memcontrol.c | 26 -------------------------- mm/oom_kill.c | 19 +++++++------------ 5 files changed, 9 insertions(+), 47 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index b8d5d100ed4a..5eacce5e924a 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -532,7 +532,7 @@ static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns, unsigned long totalpages = totalram_pages() + total_swap_pages; unsigned long points = 0; - points = oom_badness(task, NULL, NULL, totalpages) * + points = oom_badness(task, NULL, totalpages) * 1000 / totalpages; seq_printf(m, "%lu\n", points); diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 9abf31bbe53a..2cbce1fe7780 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -407,7 +407,6 @@ static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat, struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *); -bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg); struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm); @@ -896,12 +895,6 @@ static inline bool mm_match_cgroup(struct mm_struct *mm, return true; } -static inline bool task_in_mem_cgroup(struct task_struct *task, - const struct mem_cgroup *memcg) -{ - return true; -} - static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) { return NULL; diff --git a/include/linux/oom.h b/include/linux/oom.h index d07992009265..b75104690311 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -108,7 +108,7 @@ static inline vm_fault_t check_stable_address_space(struct mm_struct *mm) bool __oom_reap_task_mm(struct mm_struct *mm); extern unsigned long oom_badness(struct task_struct *p, - struct mem_cgroup *memcg, const nodemask_t *nodemask, + const nodemask_t *nodemask, unsigned long totalpages); extern bool out_of_memory(struct oom_control *oc); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index db46a9dc37ab..27c92c2b99be 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1259,32 +1259,6 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, *lru_size += nr_pages; } -bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg) -{ - struct mem_cgroup *task_memcg; - struct task_struct *p; - bool ret; - - p = find_lock_task_mm(task); - if (p) { - task_memcg = get_mem_cgroup_from_mm(p->mm); - task_unlock(p); - } else { - /* - * All threads may have already detached their mm's, but the oom - * killer still needs to detect if they have already been oom - * killed to prevent needlessly killing additional tasks. - */ - rcu_read_lock(); - task_memcg = mem_cgroup_from_task(task); - css_get(&task_memcg->css); - rcu_read_unlock(); - } - ret = mem_cgroup_is_descendant(task_memcg, memcg); - css_put(&task_memcg->css); - return ret; -} - /** * mem_cgroup_margin - calculate chargeable space of a memory cgroup * @memcg: the memory cgroup diff --git a/mm/oom_kill.c b/mm/oom_kill.c index bd80997e0969..e0cdcbd58b0b 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -153,17 +153,13 @@ static inline bool is_memcg_oom(struct oom_control *oc) /* return true if the task is not adequate as candidate victim task. */ static bool oom_unkillable_task(struct task_struct *p, - struct mem_cgroup *memcg, const nodemask_t *nodemask) + const nodemask_t *nodemask) { if (is_global_init(p)) return true; if (p->flags & PF_KTHREAD) return true; - /* When mem_cgroup_out_of_memory() and p is not member of the group */ - if (memcg && !task_in_mem_cgroup(p, memcg)) - return true; - /* p may not have freeable memory in nodemask */ if (!has_intersects_mems_allowed(p, nodemask)) return true; @@ -194,20 +190,19 @@ static bool is_dump_unreclaim_slabs(void) * oom_badness - heuristic function to determine which candidate task to kill * @p: task struct of which task we should calculate * @totalpages: total present RAM allowed for page allocation - * @memcg: task's memory controller, if constrained * @nodemask: nodemask passed to page allocator for mempolicy ooms * * The heuristic for determining which task to kill is made to be as simple and * predictable as possible. The goal is to return the highest value for the * task consuming the most memory to avoid subsequent oom failures. */ -unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, +unsigned long oom_badness(struct task_struct *p, const nodemask_t *nodemask, unsigned long totalpages) { long points; long adj; - if (oom_unkillable_task(p, memcg, nodemask)) + if (oom_unkillable_task(p, nodemask)) return 0; p = find_lock_task_mm(p); @@ -318,7 +313,7 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) struct oom_control *oc = arg; unsigned long points; - if (oom_unkillable_task(task, NULL, oc->nodemask)) + if (oom_unkillable_task(task, oc->nodemask)) goto next; /* @@ -342,7 +337,7 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) goto select; } - points = oom_badness(task, NULL, oc->nodemask, oc->totalpages); + points = oom_badness(task, oc->nodemask, oc->totalpages); if (!points || points < oc->chosen_points) goto next; @@ -390,7 +385,7 @@ static int dump_task(struct task_struct *p, void *arg) struct oom_control *oc = arg; struct task_struct *task; - if (oom_unkillable_task(p, NULL, oc->nodemask)) + if (oom_unkillable_task(p, oc->nodemask)) return 0; task = find_lock_task_mm(p); @@ -1090,7 +1085,7 @@ bool out_of_memory(struct oom_control *oc) check_panic_on_oom(oc, constraint); if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task && - current->mm && !oom_unkillable_task(current, NULL, oc->nodemask) && + current->mm && !oom_unkillable_task(current, oc->nodemask) && current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) { get_task_struct(current); oc->chosen = current; -- 2.22.0.410.gd8fdbe21b5-goog ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v3 2/3] mm, oom: remove redundant task_in_mem_cgroup() check 2019-06-24 21:26 ` [PATCH v3 2/3] mm, oom: remove redundant task_in_mem_cgroup() check Shakeel Butt @ 2019-06-26 6:38 ` Michal Hocko 2019-06-28 2:12 ` Shakeel Butt 0 siblings, 1 reply; 9+ messages in thread From: Michal Hocko @ 2019-06-26 6:38 UTC (permalink / raw) To: Shakeel Butt Cc: Johannes Weiner, Vladimir Davydov, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, linux-mm, linux-kernel On Mon 24-06-19 14:26:30, Shakeel Butt wrote: > oom_unkillable_task() can be called from three different contexts i.e. > global OOM, memcg OOM and oom_score procfs interface. At the moment > oom_unkillable_task() does a task_in_mem_cgroup() check on the given > process. Since there is no reason to perform task_in_mem_cgroup() > check for global OOM and oom_score procfs interface, those contexts > provide NULL memcg and skips the task_in_mem_cgroup() check. However for > memcg OOM context, the oom_unkillable_task() is always called from > mem_cgroup_scan_tasks() and thus task_in_mem_cgroup() check becomes > redundant. So, just remove the task_in_mem_cgroup() check altogether. Just a nit. Not only it is redundant but it is effectively a dead code after your previous patch. > Signed-off-by: Shakeel Butt <shakeelb@google.com> > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Thanks! > --- > Changelog since v2: > - Further divided the patch into two patches. > - Incorporated the task_in_mem_cgroup() from Tetsuo. > > Changelog since v1: > - Divide the patch into two patches. > > fs/proc/base.c | 2 +- > include/linux/memcontrol.h | 7 ------- > include/linux/oom.h | 2 +- > mm/memcontrol.c | 26 -------------------------- > mm/oom_kill.c | 19 +++++++------------ > 5 files changed, 9 insertions(+), 47 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index b8d5d100ed4a..5eacce5e924a 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -532,7 +532,7 @@ static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns, > unsigned long totalpages = totalram_pages() + total_swap_pages; > unsigned long points = 0; > > - points = oom_badness(task, NULL, NULL, totalpages) * > + points = oom_badness(task, NULL, totalpages) * > 1000 / totalpages; > seq_printf(m, "%lu\n", points); > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 9abf31bbe53a..2cbce1fe7780 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -407,7 +407,6 @@ static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat, > > struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *); > > -bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg); > struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); > > struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm); > @@ -896,12 +895,6 @@ static inline bool mm_match_cgroup(struct mm_struct *mm, > return true; > } > > -static inline bool task_in_mem_cgroup(struct task_struct *task, > - const struct mem_cgroup *memcg) > -{ > - return true; > -} > - > static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) > { > return NULL; > diff --git a/include/linux/oom.h b/include/linux/oom.h > index d07992009265..b75104690311 100644 > --- a/include/linux/oom.h > +++ b/include/linux/oom.h > @@ -108,7 +108,7 @@ static inline vm_fault_t check_stable_address_space(struct mm_struct *mm) > bool __oom_reap_task_mm(struct mm_struct *mm); > > extern unsigned long oom_badness(struct task_struct *p, > - struct mem_cgroup *memcg, const nodemask_t *nodemask, > + const nodemask_t *nodemask, > unsigned long totalpages); > > extern bool out_of_memory(struct oom_control *oc); > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index db46a9dc37ab..27c92c2b99be 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1259,32 +1259,6 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, > *lru_size += nr_pages; > } > > -bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg) > -{ > - struct mem_cgroup *task_memcg; > - struct task_struct *p; > - bool ret; > - > - p = find_lock_task_mm(task); > - if (p) { > - task_memcg = get_mem_cgroup_from_mm(p->mm); > - task_unlock(p); > - } else { > - /* > - * All threads may have already detached their mm's, but the oom > - * killer still needs to detect if they have already been oom > - * killed to prevent needlessly killing additional tasks. > - */ > - rcu_read_lock(); > - task_memcg = mem_cgroup_from_task(task); > - css_get(&task_memcg->css); > - rcu_read_unlock(); > - } > - ret = mem_cgroup_is_descendant(task_memcg, memcg); > - css_put(&task_memcg->css); > - return ret; > -} > - > /** > * mem_cgroup_margin - calculate chargeable space of a memory cgroup > * @memcg: the memory cgroup > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index bd80997e0969..e0cdcbd58b0b 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -153,17 +153,13 @@ static inline bool is_memcg_oom(struct oom_control *oc) > > /* return true if the task is not adequate as candidate victim task. */ > static bool oom_unkillable_task(struct task_struct *p, > - struct mem_cgroup *memcg, const nodemask_t *nodemask) > + const nodemask_t *nodemask) > { > if (is_global_init(p)) > return true; > if (p->flags & PF_KTHREAD) > return true; > > - /* When mem_cgroup_out_of_memory() and p is not member of the group */ > - if (memcg && !task_in_mem_cgroup(p, memcg)) > - return true; > - > /* p may not have freeable memory in nodemask */ > if (!has_intersects_mems_allowed(p, nodemask)) > return true; > @@ -194,20 +190,19 @@ static bool is_dump_unreclaim_slabs(void) > * oom_badness - heuristic function to determine which candidate task to kill > * @p: task struct of which task we should calculate > * @totalpages: total present RAM allowed for page allocation > - * @memcg: task's memory controller, if constrained > * @nodemask: nodemask passed to page allocator for mempolicy ooms > * > * The heuristic for determining which task to kill is made to be as simple and > * predictable as possible. The goal is to return the highest value for the > * task consuming the most memory to avoid subsequent oom failures. > */ > -unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, > +unsigned long oom_badness(struct task_struct *p, > const nodemask_t *nodemask, unsigned long totalpages) > { > long points; > long adj; > > - if (oom_unkillable_task(p, memcg, nodemask)) > + if (oom_unkillable_task(p, nodemask)) > return 0; > > p = find_lock_task_mm(p); > @@ -318,7 +313,7 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) > struct oom_control *oc = arg; > unsigned long points; > > - if (oom_unkillable_task(task, NULL, oc->nodemask)) > + if (oom_unkillable_task(task, oc->nodemask)) > goto next; > > /* > @@ -342,7 +337,7 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) > goto select; > } > > - points = oom_badness(task, NULL, oc->nodemask, oc->totalpages); > + points = oom_badness(task, oc->nodemask, oc->totalpages); > if (!points || points < oc->chosen_points) > goto next; > > @@ -390,7 +385,7 @@ static int dump_task(struct task_struct *p, void *arg) > struct oom_control *oc = arg; > struct task_struct *task; > > - if (oom_unkillable_task(p, NULL, oc->nodemask)) > + if (oom_unkillable_task(p, oc->nodemask)) > return 0; > > task = find_lock_task_mm(p); > @@ -1090,7 +1085,7 @@ bool out_of_memory(struct oom_control *oc) > check_panic_on_oom(oc, constraint); > > if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task && > - current->mm && !oom_unkillable_task(current, NULL, oc->nodemask) && > + current->mm && !oom_unkillable_task(current, oc->nodemask) && > current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) { > get_task_struct(current); > oc->chosen = current; > -- > 2.22.0.410.gd8fdbe21b5-goog -- Michal Hocko SUSE Labs ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 2/3] mm, oom: remove redundant task_in_mem_cgroup() check 2019-06-26 6:38 ` Michal Hocko @ 2019-06-28 2:12 ` Shakeel Butt 0 siblings, 0 replies; 9+ messages in thread From: Shakeel Butt @ 2019-06-28 2:12 UTC (permalink / raw) To: Michal Hocko Cc: Johannes Weiner, Vladimir Davydov, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, Linux MM, LKML On Tue, Jun 25, 2019 at 11:38 PM Michal Hocko <mhocko@kernel.org> wrote: > > On Mon 24-06-19 14:26:30, Shakeel Butt wrote: > > oom_unkillable_task() can be called from three different contexts i.e. > > global OOM, memcg OOM and oom_score procfs interface. At the moment > > oom_unkillable_task() does a task_in_mem_cgroup() check on the given > > process. Since there is no reason to perform task_in_mem_cgroup() > > check for global OOM and oom_score procfs interface, those contexts > > provide NULL memcg and skips the task_in_mem_cgroup() check. However for > > memcg OOM context, the oom_unkillable_task() is always called from > > mem_cgroup_scan_tasks() and thus task_in_mem_cgroup() check becomes > > redundant. So, just remove the task_in_mem_cgroup() check altogether. > > Just a nit. Not only it is redundant but it is effectively a dead code > after your previous patch. > I will update the commit message. > > Signed-off-by: Shakeel Butt <shakeelb@google.com> > > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > > Acked-by: Michal Hocko <mhocko@suse.com> Thanks ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task 2019-06-24 21:26 [PATCH v3 1/3] mm, oom: refactor dump_tasks for memcg OOMs Shakeel Butt 2019-06-24 21:26 ` [PATCH v3 2/3] mm, oom: remove redundant task_in_mem_cgroup() check Shakeel Butt @ 2019-06-24 21:26 ` Shakeel Butt 2019-06-26 6:55 ` Michal Hocko ` (2 more replies) 1 sibling, 3 replies; 9+ messages in thread From: Shakeel Butt @ 2019-06-24 21:26 UTC (permalink / raw) To: Johannes Weiner, Vladimir Davydov, Michal Hocko, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, Nick Piggin Cc: linux-mm, linux-kernel, Shakeel Butt, syzbot+d0fc9d3c166bc5e4a94b The commit ef08e3b4981a ("[PATCH] cpusets: confine oom_killer to mem_exclusive cpuset") introduces a heuristic where a potential oom-killer victim is skipped if the intersection of the potential victim and the current (the process triggered the oom) is empty based on the reason that killing such victim most probably will not help the current allocating process. However the commit 7887a3da753e ("[PATCH] oom: cpuset hint") changed the heuristic to just decrease the oom_badness scores of such potential victim based on the reason that the cpuset of such processes might have changed and previously they might have allocated memory on mems where the current allocating process can allocate from. Unintentionally commit 7887a3da753e ("[PATCH] oom: cpuset hint") introduced a side effect as the oom_badness is also exposed to the user space through /proc/[pid]/oom_score, so, readers with different cpusets can read different oom_score of th same process. Later the commit 6cf86ac6f36b ("oom: filter tasks not sharing the same cpuset") fixed the side effect introduced by 7887a3da753e by moving the cpuset intersection back to only oom-killer context and out of oom_badness. However the combination of the commit ab290adbaf8f ("oom: make oom_unkillable_task() helper function") and commit 26ebc984913b ("oom: /proc/<pid>/oom_score treat kernel thread honestly") unintentionally brought back the cpuset intersection check into the oom_badness calculation function. Other than doing cpuset/mempolicy intersection from oom_badness, the memcg oom context is also doing cpuset/mempolicy intersection which is quite wrong and is caught by syzcaller with the following report: kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 28426 Comm: syz-executor.5 Not tainted 5.2.0-rc3-next-20190607 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff RSP: 0018:ffff888000127490 EFLAGS: 00010a03 RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000607304 CR3: 000000009237e000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: oom_evaluate_task+0x49/0x520 mm/oom_kill.c:321 mem_cgroup_scan_tasks+0xcc/0x180 mm/memcontrol.c:1169 select_bad_process mm/oom_kill.c:374 [inline] out_of_memory mm/oom_kill.c:1088 [inline] out_of_memory+0x6b2/0x1280 mm/oom_kill.c:1035 mem_cgroup_out_of_memory+0x1ca/0x230 mm/memcontrol.c:1573 mem_cgroup_oom mm/memcontrol.c:1905 [inline] try_charge+0xfbe/0x1480 mm/memcontrol.c:2468 mem_cgroup_try_charge+0x24d/0x5e0 mm/memcontrol.c:6073 mem_cgroup_try_charge_delay+0x1f/0xa0 mm/memcontrol.c:6088 do_huge_pmd_wp_page_fallback+0x24f/0x1680 mm/huge_memory.c:1201 do_huge_pmd_wp_page+0x7fc/0x2160 mm/huge_memory.c:1359 wp_huge_pmd mm/memory.c:3793 [inline] __handle_mm_fault+0x164c/0x3eb0 mm/memory.c:4006 handle_mm_fault+0x3b7/0xa90 mm/memory.c:4053 do_user_addr_fault arch/x86/mm/fault.c:1455 [inline] __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1521 do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1552 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1156 RIP: 0033:0x400590 Code: 06 e9 49 01 00 00 48 8b 44 24 10 48 0b 44 24 28 75 1f 48 8b 14 24 48 8b 7c 24 20 be 04 00 00 00 e8 f5 56 00 00 48 8b 74 24 08 <89> 06 e9 1e 01 00 00 48 8b 44 24 08 48 8b 14 24 be 04 00 00 00 8b RSP: 002b:00007fff7bc49780 EFLAGS: 00010206 RAX: 0000000000000001 RBX: 0000000000760000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000000002000cffc RDI: 0000000000000001 RBP: fffffffffffffffe R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000760008 R13: 00000000004c55f2 R14: 0000000000000000 R15: 00007fff7bc499b0 Modules linked in: ---[ end trace a65689219582ffff ]--- RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff RSP: 0018:ffff888000127490 EFLAGS: 00010a03 RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f823000 CR3: 000000009237e000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 The fix is to decouple the cpuset/mempolicy intersection check from oom_unkillable_task() and make sure cpuset/mempolicy intersection check is only done in the global oom context. Reported-by: syzbot+d0fc9d3c166bc5e4a94b@syzkaller.appspotmail.com Signed-off-by: Shakeel Butt <shakeelb@google.com> --- Changelog since v2: - Further divided the patch into two patches. - More cleaned version. Changelog since v1: - Divide the patch into two patches. fs/proc/base.c | 3 +-- include/linux/oom.h | 1 - mm/oom_kill.c | 51 ++++++++++++++++++++++++++------------------- 3 files changed, 30 insertions(+), 25 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 5eacce5e924a..57b7a0d75ef5 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -532,8 +532,7 @@ static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns, unsigned long totalpages = totalram_pages() + total_swap_pages; unsigned long points = 0; - points = oom_badness(task, NULL, totalpages) * - 1000 / totalpages; + points = oom_badness(task, totalpages) * 1000 / totalpages; seq_printf(m, "%lu\n", points); return 0; diff --git a/include/linux/oom.h b/include/linux/oom.h index b75104690311..c696c265f019 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -108,7 +108,6 @@ static inline vm_fault_t check_stable_address_space(struct mm_struct *mm) bool __oom_reap_task_mm(struct mm_struct *mm); extern unsigned long oom_badness(struct task_struct *p, - const nodemask_t *nodemask, unsigned long totalpages); extern bool out_of_memory(struct oom_control *oc); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index e0cdcbd58b0b..9f91cb7036fb 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -64,6 +64,11 @@ int sysctl_oom_dump_tasks = 1; */ DEFINE_MUTEX(oom_lock); +static inline bool is_memcg_oom(struct oom_control *oc) +{ + return oc->memcg != NULL; +} + #ifdef CONFIG_NUMA /** * has_intersects_mems_allowed() - check task eligiblity for kill @@ -73,12 +78,18 @@ DEFINE_MUTEX(oom_lock); * Task eligibility is determined by whether or not a candidate task, @tsk, * shares the same mempolicy nodes as current if it is bound by such a policy * and whether or not it has the same set of allowed cpuset nodes. + * + * Only call in the global oom context (i.e. not in memcg oom). This function + * is assuming 'current' has triggered the oom-killer. */ static bool has_intersects_mems_allowed(struct task_struct *start, - const nodemask_t *mask) + struct oom_control *oc) { struct task_struct *tsk; bool ret = false; + const nodemask_t *mask = oc->nodemask; + + VM_BUG_ON(is_memcg_oom(oc)); rcu_read_lock(); for_each_thread(start, tsk) { @@ -106,7 +117,7 @@ static bool has_intersects_mems_allowed(struct task_struct *start, } #else static bool has_intersects_mems_allowed(struct task_struct *tsk, - const nodemask_t *mask) + struct oom_control *oc) { return true; } @@ -146,24 +157,13 @@ static inline bool is_sysrq_oom(struct oom_control *oc) return oc->order == -1; } -static inline bool is_memcg_oom(struct oom_control *oc) -{ - return oc->memcg != NULL; -} - /* return true if the task is not adequate as candidate victim task. */ -static bool oom_unkillable_task(struct task_struct *p, - const nodemask_t *nodemask) +static bool oom_unkillable_task(struct task_struct *p) { if (is_global_init(p)) return true; if (p->flags & PF_KTHREAD) return true; - - /* p may not have freeable memory in nodemask */ - if (!has_intersects_mems_allowed(p, nodemask)) - return true; - return false; } @@ -190,19 +190,17 @@ static bool is_dump_unreclaim_slabs(void) * oom_badness - heuristic function to determine which candidate task to kill * @p: task struct of which task we should calculate * @totalpages: total present RAM allowed for page allocation - * @nodemask: nodemask passed to page allocator for mempolicy ooms * * The heuristic for determining which task to kill is made to be as simple and * predictable as possible. The goal is to return the highest value for the * task consuming the most memory to avoid subsequent oom failures. */ -unsigned long oom_badness(struct task_struct *p, - const nodemask_t *nodemask, unsigned long totalpages) +unsigned long oom_badness(struct task_struct *p, unsigned long totalpages) { long points; long adj; - if (oom_unkillable_task(p, nodemask)) + if (oom_unkillable_task(p)) return 0; p = find_lock_task_mm(p); @@ -313,7 +311,11 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) struct oom_control *oc = arg; unsigned long points; - if (oom_unkillable_task(task, oc->nodemask)) + if (oom_unkillable_task(task)) + goto next; + + /* p may not have freeable memory in nodemask */ + if (!is_memcg_oom(oc) && !has_intersects_mems_allowed(task, oc)) goto next; /* @@ -337,7 +339,7 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) goto select; } - points = oom_badness(task, oc->nodemask, oc->totalpages); + points = oom_badness(task, oc->totalpages); if (!points || points < oc->chosen_points) goto next; @@ -385,7 +387,11 @@ static int dump_task(struct task_struct *p, void *arg) struct oom_control *oc = arg; struct task_struct *task; - if (oom_unkillable_task(p, oc->nodemask)) + if (oom_unkillable_task(p)) + return 0; + + /* p may not have freeable memory in nodemask */ + if (!is_memcg_oom(oc) && !has_intersects_mems_allowed(p, oc)) return 0; task = find_lock_task_mm(p); @@ -1085,7 +1091,8 @@ bool out_of_memory(struct oom_control *oc) check_panic_on_oom(oc, constraint); if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task && - current->mm && !oom_unkillable_task(current, oc->nodemask) && + current->mm && !oom_unkillable_task(current) && + has_intersects_mems_allowed(current, oc) && current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) { get_task_struct(current); oc->chosen = current; -- 2.22.0.410.gd8fdbe21b5-goog ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task 2019-06-24 21:26 ` [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task Shakeel Butt @ 2019-06-26 6:55 ` Michal Hocko 2019-06-28 2:17 ` Shakeel Butt 2019-06-26 9:18 ` Michal Hocko 2019-06-26 19:47 ` Roman Gushchin 2 siblings, 1 reply; 9+ messages in thread From: Michal Hocko @ 2019-06-26 6:55 UTC (permalink / raw) To: Shakeel Butt Cc: Johannes Weiner, Vladimir Davydov, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, linux-mm, linux-kernel, syzbot+d0fc9d3c166bc5e4a94b On Mon 24-06-19 14:26:31, Shakeel Butt wrote: > The commit ef08e3b4981a ("[PATCH] cpusets: confine oom_killer to > mem_exclusive cpuset") introduces a heuristic where a potential > oom-killer victim is skipped if the intersection of the potential victim > and the current (the process triggered the oom) is empty based on the > reason that killing such victim most probably will not help the current > allocating process. However the commit 7887a3da753e ("[PATCH] oom: > cpuset hint") changed the heuristic to just decrease the oom_badness > scores of such potential victim based on the reason that the cpuset of > such processes might have changed and previously they might have > allocated memory on mems where the current allocating process can > allocate from. > > Unintentionally commit 7887a3da753e ("[PATCH] oom: cpuset hint") > introduced a side effect as the oom_badness is also exposed to the > user space through /proc/[pid]/oom_score, so, readers with different > cpusets can read different oom_score of th same process. > > Later the commit 6cf86ac6f36b ("oom: filter tasks not sharing the same > cpuset") fixed the side effect introduced by 7887a3da753e by moving the > cpuset intersection back to only oom-killer context and out of > oom_badness. However the combination of the commit ab290adbaf8f ("oom: > make oom_unkillable_task() helper function") and commit 26ebc984913b > ("oom: /proc/<pid>/oom_score treat kernel thread honestly") > unintentionally brought back the cpuset intersection check into the > oom_badness calculation function. Thanks for this excursion into the history. I think it is very useful. > Other than doing cpuset/mempolicy intersection from oom_badness, the > memcg oom context is also doing cpuset/mempolicy intersection which is > quite wrong and is caught by syzcaller with the following report: > > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 28426 Comm: syz-executor.5 Not tainted 5.2.0-rc3-next-20190607 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] > RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] > RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] > RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 > Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 > 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f > 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff > RSP: 0018:ffff888000127490 EFLAGS: 00010a03 > RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c > RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 > RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 > R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 > R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 > FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000607304 CR3: 000000009237e000 CR4: 00000000001426f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > Call Trace: > oom_evaluate_task+0x49/0x520 mm/oom_kill.c:321 > mem_cgroup_scan_tasks+0xcc/0x180 mm/memcontrol.c:1169 > select_bad_process mm/oom_kill.c:374 [inline] > out_of_memory mm/oom_kill.c:1088 [inline] > out_of_memory+0x6b2/0x1280 mm/oom_kill.c:1035 > mem_cgroup_out_of_memory+0x1ca/0x230 mm/memcontrol.c:1573 > mem_cgroup_oom mm/memcontrol.c:1905 [inline] > try_charge+0xfbe/0x1480 mm/memcontrol.c:2468 > mem_cgroup_try_charge+0x24d/0x5e0 mm/memcontrol.c:6073 > mem_cgroup_try_charge_delay+0x1f/0xa0 mm/memcontrol.c:6088 > do_huge_pmd_wp_page_fallback+0x24f/0x1680 mm/huge_memory.c:1201 > do_huge_pmd_wp_page+0x7fc/0x2160 mm/huge_memory.c:1359 > wp_huge_pmd mm/memory.c:3793 [inline] > __handle_mm_fault+0x164c/0x3eb0 mm/memory.c:4006 > handle_mm_fault+0x3b7/0xa90 mm/memory.c:4053 > do_user_addr_fault arch/x86/mm/fault.c:1455 [inline] > __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1521 > do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1552 > page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1156 > RIP: 0033:0x400590 > Code: 06 e9 49 01 00 00 48 8b 44 24 10 48 0b 44 24 28 75 1f 48 8b 14 24 48 > 8b 7c 24 20 be 04 00 00 00 e8 f5 56 00 00 48 8b 74 24 08 <89> 06 e9 1e 01 > 00 00 48 8b 44 24 08 48 8b 14 24 be 04 00 00 00 8b > RSP: 002b:00007fff7bc49780 EFLAGS: 00010206 > RAX: 0000000000000001 RBX: 0000000000760000 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 000000002000cffc RDI: 0000000000000001 > RBP: fffffffffffffffe R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000760008 > R13: 00000000004c55f2 R14: 0000000000000000 R15: 00007fff7bc499b0 > Modules linked in: > ---[ end trace a65689219582ffff ]--- > RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] > RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] > RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] > RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 > Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 > 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f > 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff > RSP: 0018:ffff888000127490 EFLAGS: 00010a03 > RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c > RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 > RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 > R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 > R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 > FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000001b2f823000 CR3: 000000009237e000 CR4: 00000000001426f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > > The fix is to decouple the cpuset/mempolicy intersection check from > oom_unkillable_task() and make sure cpuset/mempolicy intersection check > is only done in the global oom context. Thanks for the changelog update. This looks really great to me. > Reported-by: syzbot+d0fc9d3c166bc5e4a94b@syzkaller.appspotmail.com > Signed-off-by: Shakeel Butt <shakeelb@google.com> I think that VM_BUG_ON in has_intersects_mems_allowed is over protective and it makes the rest of the code a bit more convoluted than necessary. Is there any reason we just do the check and return true there? Btw. has_intersects_mems_allowed sounds like a misnomer to me. It suggests to be a more generic function while it has some memcg implications which are not trivial to spot without digging deeper. I would go with oom_cpuset_eligible or something along those lines. Anyway Acked-by: Michal Hocko <mhocko@suse.com> > --- > Changelog since v2: > - Further divided the patch into two patches. > - More cleaned version. > > Changelog since v1: > - Divide the patch into two patches. > > fs/proc/base.c | 3 +-- > include/linux/oom.h | 1 - > mm/oom_kill.c | 51 ++++++++++++++++++++++++++------------------- > 3 files changed, 30 insertions(+), 25 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 5eacce5e924a..57b7a0d75ef5 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -532,8 +532,7 @@ static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns, > unsigned long totalpages = totalram_pages() + total_swap_pages; > unsigned long points = 0; > > - points = oom_badness(task, NULL, totalpages) * > - 1000 / totalpages; > + points = oom_badness(task, totalpages) * 1000 / totalpages; > seq_printf(m, "%lu\n", points); > > return 0; > diff --git a/include/linux/oom.h b/include/linux/oom.h > index b75104690311..c696c265f019 100644 > --- a/include/linux/oom.h > +++ b/include/linux/oom.h > @@ -108,7 +108,6 @@ static inline vm_fault_t check_stable_address_space(struct mm_struct *mm) > bool __oom_reap_task_mm(struct mm_struct *mm); > > extern unsigned long oom_badness(struct task_struct *p, > - const nodemask_t *nodemask, > unsigned long totalpages); > > extern bool out_of_memory(struct oom_control *oc); > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index e0cdcbd58b0b..9f91cb7036fb 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -64,6 +64,11 @@ int sysctl_oom_dump_tasks = 1; > */ > DEFINE_MUTEX(oom_lock); > > +static inline bool is_memcg_oom(struct oom_control *oc) > +{ > + return oc->memcg != NULL; > +} > + > #ifdef CONFIG_NUMA > /** > * has_intersects_mems_allowed() - check task eligiblity for kill > @@ -73,12 +78,18 @@ DEFINE_MUTEX(oom_lock); > * Task eligibility is determined by whether or not a candidate task, @tsk, > * shares the same mempolicy nodes as current if it is bound by such a policy > * and whether or not it has the same set of allowed cpuset nodes. > + * > + * Only call in the global oom context (i.e. not in memcg oom). This function > + * is assuming 'current' has triggered the oom-killer. > */ > static bool has_intersects_mems_allowed(struct task_struct *start, > - const nodemask_t *mask) > + struct oom_control *oc) > { > struct task_struct *tsk; > bool ret = false; > + const nodemask_t *mask = oc->nodemask; > + > + VM_BUG_ON(is_memcg_oom(oc)); > > rcu_read_lock(); > for_each_thread(start, tsk) { > @@ -106,7 +117,7 @@ static bool has_intersects_mems_allowed(struct task_struct *start, > } > #else > static bool has_intersects_mems_allowed(struct task_struct *tsk, > - const nodemask_t *mask) > + struct oom_control *oc) > { > return true; > } > @@ -146,24 +157,13 @@ static inline bool is_sysrq_oom(struct oom_control *oc) > return oc->order == -1; > } > > -static inline bool is_memcg_oom(struct oom_control *oc) > -{ > - return oc->memcg != NULL; > -} > - > /* return true if the task is not adequate as candidate victim task. */ > -static bool oom_unkillable_task(struct task_struct *p, > - const nodemask_t *nodemask) > +static bool oom_unkillable_task(struct task_struct *p) > { > if (is_global_init(p)) > return true; > if (p->flags & PF_KTHREAD) > return true; > - > - /* p may not have freeable memory in nodemask */ > - if (!has_intersects_mems_allowed(p, nodemask)) > - return true; > - > return false; > } > > @@ -190,19 +190,17 @@ static bool is_dump_unreclaim_slabs(void) > * oom_badness - heuristic function to determine which candidate task to kill > * @p: task struct of which task we should calculate > * @totalpages: total present RAM allowed for page allocation > - * @nodemask: nodemask passed to page allocator for mempolicy ooms > * > * The heuristic for determining which task to kill is made to be as simple and > * predictable as possible. The goal is to return the highest value for the > * task consuming the most memory to avoid subsequent oom failures. > */ > -unsigned long oom_badness(struct task_struct *p, > - const nodemask_t *nodemask, unsigned long totalpages) > +unsigned long oom_badness(struct task_struct *p, unsigned long totalpages) > { > long points; > long adj; > > - if (oom_unkillable_task(p, nodemask)) > + if (oom_unkillable_task(p)) > return 0; > > p = find_lock_task_mm(p); > @@ -313,7 +311,11 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) > struct oom_control *oc = arg; > unsigned long points; > > - if (oom_unkillable_task(task, oc->nodemask)) > + if (oom_unkillable_task(task)) > + goto next; > + > + /* p may not have freeable memory in nodemask */ > + if (!is_memcg_oom(oc) && !has_intersects_mems_allowed(task, oc)) > goto next; > > /* > @@ -337,7 +339,7 @@ static int oom_evaluate_task(struct task_struct *task, void *arg) > goto select; > } > > - points = oom_badness(task, oc->nodemask, oc->totalpages); > + points = oom_badness(task, oc->totalpages); > if (!points || points < oc->chosen_points) > goto next; > > @@ -385,7 +387,11 @@ static int dump_task(struct task_struct *p, void *arg) > struct oom_control *oc = arg; > struct task_struct *task; > > - if (oom_unkillable_task(p, oc->nodemask)) > + if (oom_unkillable_task(p)) > + return 0; > + > + /* p may not have freeable memory in nodemask */ > + if (!is_memcg_oom(oc) && !has_intersects_mems_allowed(p, oc)) > return 0; > > task = find_lock_task_mm(p); > @@ -1085,7 +1091,8 @@ bool out_of_memory(struct oom_control *oc) > check_panic_on_oom(oc, constraint); > > if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task && > - current->mm && !oom_unkillable_task(current, oc->nodemask) && > + current->mm && !oom_unkillable_task(current) && > + has_intersects_mems_allowed(current, oc) && > current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) { > get_task_struct(current); > oc->chosen = current; > -- > 2.22.0.410.gd8fdbe21b5-goog -- Michal Hocko SUSE Labs ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task 2019-06-26 6:55 ` Michal Hocko @ 2019-06-28 2:17 ` Shakeel Butt 0 siblings, 0 replies; 9+ messages in thread From: Shakeel Butt @ 2019-06-28 2:17 UTC (permalink / raw) To: Michal Hocko Cc: Johannes Weiner, Vladimir Davydov, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, Linux MM, LKML, syzbot On Tue, Jun 25, 2019 at 11:55 PM Michal Hocko <mhocko@kernel.org> wrote: > > On Mon 24-06-19 14:26:31, Shakeel Butt wrote: > > The commit ef08e3b4981a ("[PATCH] cpusets: confine oom_killer to > > mem_exclusive cpuset") introduces a heuristic where a potential > > oom-killer victim is skipped if the intersection of the potential victim > > and the current (the process triggered the oom) is empty based on the > > reason that killing such victim most probably will not help the current > > allocating process. However the commit 7887a3da753e ("[PATCH] oom: > > cpuset hint") changed the heuristic to just decrease the oom_badness > > scores of such potential victim based on the reason that the cpuset of > > such processes might have changed and previously they might have > > allocated memory on mems where the current allocating process can > > allocate from. > > > > Unintentionally commit 7887a3da753e ("[PATCH] oom: cpuset hint") > > introduced a side effect as the oom_badness is also exposed to the > > user space through /proc/[pid]/oom_score, so, readers with different > > cpusets can read different oom_score of th same process. > > > > Later the commit 6cf86ac6f36b ("oom: filter tasks not sharing the same > > cpuset") fixed the side effect introduced by 7887a3da753e by moving the > > cpuset intersection back to only oom-killer context and out of > > oom_badness. However the combination of the commit ab290adbaf8f ("oom: > > make oom_unkillable_task() helper function") and commit 26ebc984913b > > ("oom: /proc/<pid>/oom_score treat kernel thread honestly") > > unintentionally brought back the cpuset intersection check into the > > oom_badness calculation function. > > Thanks for this excursion into the history. I think it is very useful. > > > Other than doing cpuset/mempolicy intersection from oom_badness, the > > memcg oom context is also doing cpuset/mempolicy intersection which is > > quite wrong and is caught by syzcaller with the following report: > > > > kasan: CONFIG_KASAN_INLINE enabled > > kasan: GPF could be caused by NULL-ptr deref or user memory access > > general protection fault: 0000 [#1] PREEMPT SMP KASAN > > CPU: 0 PID: 28426 Comm: syz-executor.5 Not tainted 5.2.0-rc3-next-20190607 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] > > RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] > > RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] > > RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 > > Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 > > 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f > > 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff > > RSP: 0018:ffff888000127490 EFLAGS: 00010a03 > > RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c > > RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 > > RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 > > R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 > > R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 > > FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000000000607304 CR3: 000000009237e000 CR4: 00000000001426f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > > Call Trace: > > oom_evaluate_task+0x49/0x520 mm/oom_kill.c:321 > > mem_cgroup_scan_tasks+0xcc/0x180 mm/memcontrol.c:1169 > > select_bad_process mm/oom_kill.c:374 [inline] > > out_of_memory mm/oom_kill.c:1088 [inline] > > out_of_memory+0x6b2/0x1280 mm/oom_kill.c:1035 > > mem_cgroup_out_of_memory+0x1ca/0x230 mm/memcontrol.c:1573 > > mem_cgroup_oom mm/memcontrol.c:1905 [inline] > > try_charge+0xfbe/0x1480 mm/memcontrol.c:2468 > > mem_cgroup_try_charge+0x24d/0x5e0 mm/memcontrol.c:6073 > > mem_cgroup_try_charge_delay+0x1f/0xa0 mm/memcontrol.c:6088 > > do_huge_pmd_wp_page_fallback+0x24f/0x1680 mm/huge_memory.c:1201 > > do_huge_pmd_wp_page+0x7fc/0x2160 mm/huge_memory.c:1359 > > wp_huge_pmd mm/memory.c:3793 [inline] > > __handle_mm_fault+0x164c/0x3eb0 mm/memory.c:4006 > > handle_mm_fault+0x3b7/0xa90 mm/memory.c:4053 > > do_user_addr_fault arch/x86/mm/fault.c:1455 [inline] > > __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1521 > > do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1552 > > page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1156 > > RIP: 0033:0x400590 > > Code: 06 e9 49 01 00 00 48 8b 44 24 10 48 0b 44 24 28 75 1f 48 8b 14 24 48 > > 8b 7c 24 20 be 04 00 00 00 e8 f5 56 00 00 48 8b 74 24 08 <89> 06 e9 1e 01 > > 00 00 48 8b 44 24 08 48 8b 14 24 be 04 00 00 00 8b > > RSP: 002b:00007fff7bc49780 EFLAGS: 00010206 > > RAX: 0000000000000001 RBX: 0000000000760000 RCX: 0000000000000000 > > RDX: 0000000000000000 RSI: 000000002000cffc RDI: 0000000000000001 > > RBP: fffffffffffffffe R08: 0000000000000000 R09: 0000000000000000 > > R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000760008 > > R13: 00000000004c55f2 R14: 0000000000000000 R15: 00007fff7bc499b0 > > Modules linked in: > > ---[ end trace a65689219582ffff ]--- > > RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] > > RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] > > RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] > > RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 > > Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 > > 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f > > 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff > > RSP: 0018:ffff888000127490 EFLAGS: 00010a03 > > RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c > > RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 > > RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 > > R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 > > R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 > > FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000001b2f823000 CR3: 000000009237e000 CR4: 00000000001426f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > > > > The fix is to decouple the cpuset/mempolicy intersection check from > > oom_unkillable_task() and make sure cpuset/mempolicy intersection check > > is only done in the global oom context. > > Thanks for the changelog update. This looks really great to me. > > > Reported-by: syzbot+d0fc9d3c166bc5e4a94b@syzkaller.appspotmail.com > > Signed-off-by: Shakeel Butt <shakeelb@google.com> > > I think that VM_BUG_ON in has_intersects_mems_allowed is over protective > and it makes the rest of the code a bit more convoluted than necessary. > Is there any reason we just do the check and return true there? Btw. > has_intersects_mems_allowed sounds like a misnomer to me. It suggests > to be a more generic function while it has some memcg implications which > are not trivial to spot without digging deeper. I would go with > oom_cpuset_eligible or something along those lines. > I will change the name to "oom_cpuset_eligible". > Anyway > Acked-by: Michal Hocko <mhocko@suse.com> Thanks. ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task 2019-06-24 21:26 ` [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task Shakeel Butt 2019-06-26 6:55 ` Michal Hocko @ 2019-06-26 9:18 ` Michal Hocko 2019-06-26 19:47 ` Roman Gushchin 2 siblings, 0 replies; 9+ messages in thread From: Michal Hocko @ 2019-06-26 9:18 UTC (permalink / raw) To: Hillf Danton Cc: Shakeel Butt, Johannes Weiner, Vladimir Davydov, Andrew Morton, Roman Gushchin, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, linux-mm, linux-kernel, syzbot+d0fc9d3c166bc5e4a94b On Wed 26-06-19 17:12:10, Hillf Danton wrote: > > On Mon, 24 Jun 2019 14:27:11 -0700 (PDT) Shakeel Butt wrote: > > > > @@ -1085,7 +1091,8 @@ bool out_of_memory(struct oom_control *oc) > > check_panic_on_oom(oc, constraint); > > > > if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task && > > - current->mm && !oom_unkillable_task(current, oc->nodemask) && > > + current->mm && !oom_unkillable_task(current) && > > + has_intersects_mems_allowed(current, oc) && > For what? This is explained in the changelog I believe - see the initial section about the history and motivation for the check. This patch removes it from oom_unkillable_task so we have to check it explicitly here. > > current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) { > > get_task_struct(current); > > oc->chosen = current; > > -- > > 2.22.0.410.gd8fdbe21b5-goog -- Michal Hocko SUSE Labs ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task 2019-06-24 21:26 ` [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task Shakeel Butt 2019-06-26 6:55 ` Michal Hocko 2019-06-26 9:18 ` Michal Hocko @ 2019-06-26 19:47 ` Roman Gushchin 2 siblings, 0 replies; 9+ messages in thread From: Roman Gushchin @ 2019-06-26 19:47 UTC (permalink / raw) To: Shakeel Butt Cc: Johannes Weiner, Vladimir Davydov, Michal Hocko, Andrew Morton, David Rientjes, KOSAKI Motohiro, Tetsuo Handa, Paul Jackson, Nick Piggin, linux-mm, linux-kernel, syzbot+d0fc9d3c166bc5e4a94b On Mon, Jun 24, 2019 at 02:26:31PM -0700, Shakeel Butt wrote: > The commit ef08e3b4981a ("[PATCH] cpusets: confine oom_killer to > mem_exclusive cpuset") introduces a heuristic where a potential > oom-killer victim is skipped if the intersection of the potential victim > and the current (the process triggered the oom) is empty based on the > reason that killing such victim most probably will not help the current > allocating process. However the commit 7887a3da753e ("[PATCH] oom: > cpuset hint") changed the heuristic to just decrease the oom_badness > scores of such potential victim based on the reason that the cpuset of > such processes might have changed and previously they might have > allocated memory on mems where the current allocating process can > allocate from. > > Unintentionally commit 7887a3da753e ("[PATCH] oom: cpuset hint") > introduced a side effect as the oom_badness is also exposed to the > user space through /proc/[pid]/oom_score, so, readers with different > cpusets can read different oom_score of th same process. > > Later the commit 6cf86ac6f36b ("oom: filter tasks not sharing the same > cpuset") fixed the side effect introduced by 7887a3da753e by moving the > cpuset intersection back to only oom-killer context and out of > oom_badness. However the combination of the commit ab290adbaf8f ("oom: > make oom_unkillable_task() helper function") and commit 26ebc984913b > ("oom: /proc/<pid>/oom_score treat kernel thread honestly") > unintentionally brought back the cpuset intersection check into the > oom_badness calculation function. > > Other than doing cpuset/mempolicy intersection from oom_badness, the > memcg oom context is also doing cpuset/mempolicy intersection which is > quite wrong and is caught by syzcaller with the following report: > > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 28426 Comm: syz-executor.5 Not tainted 5.2.0-rc3-next-20190607 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] > RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] > RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] > RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 > Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 > 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f > 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff > RSP: 0018:ffff888000127490 EFLAGS: 00010a03 > RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c > RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 > RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 > R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 > R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 > FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000607304 CR3: 000000009237e000 CR4: 00000000001426f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > Call Trace: > oom_evaluate_task+0x49/0x520 mm/oom_kill.c:321 > mem_cgroup_scan_tasks+0xcc/0x180 mm/memcontrol.c:1169 > select_bad_process mm/oom_kill.c:374 [inline] > out_of_memory mm/oom_kill.c:1088 [inline] > out_of_memory+0x6b2/0x1280 mm/oom_kill.c:1035 > mem_cgroup_out_of_memory+0x1ca/0x230 mm/memcontrol.c:1573 > mem_cgroup_oom mm/memcontrol.c:1905 [inline] > try_charge+0xfbe/0x1480 mm/memcontrol.c:2468 > mem_cgroup_try_charge+0x24d/0x5e0 mm/memcontrol.c:6073 > mem_cgroup_try_charge_delay+0x1f/0xa0 mm/memcontrol.c:6088 > do_huge_pmd_wp_page_fallback+0x24f/0x1680 mm/huge_memory.c:1201 > do_huge_pmd_wp_page+0x7fc/0x2160 mm/huge_memory.c:1359 > wp_huge_pmd mm/memory.c:3793 [inline] > __handle_mm_fault+0x164c/0x3eb0 mm/memory.c:4006 > handle_mm_fault+0x3b7/0xa90 mm/memory.c:4053 > do_user_addr_fault arch/x86/mm/fault.c:1455 [inline] > __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1521 > do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1552 > page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1156 > RIP: 0033:0x400590 > Code: 06 e9 49 01 00 00 48 8b 44 24 10 48 0b 44 24 28 75 1f 48 8b 14 24 48 > 8b 7c 24 20 be 04 00 00 00 e8 f5 56 00 00 48 8b 74 24 08 <89> 06 e9 1e 01 > 00 00 48 8b 44 24 08 48 8b 14 24 be 04 00 00 00 8b > RSP: 002b:00007fff7bc49780 EFLAGS: 00010206 > RAX: 0000000000000001 RBX: 0000000000760000 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 000000002000cffc RDI: 0000000000000001 > RBP: fffffffffffffffe R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000760008 > R13: 00000000004c55f2 R14: 0000000000000000 R15: 00007fff7bc499b0 > Modules linked in: > ---[ end trace a65689219582ffff ]--- > RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] > RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] > RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] > RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 > Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 > 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f > 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff > RSP: 0018:ffff888000127490 EFLAGS: 00010a03 > RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c > RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 > RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 > R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 > R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 > FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000001b2f823000 CR3: 000000009237e000 CR4: 00000000001426f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > > The fix is to decouple the cpuset/mempolicy intersection check from > oom_unkillable_task() and make sure cpuset/mempolicy intersection check > is only done in the global oom context. > > Reported-by: syzbot+d0fc9d3c166bc5e4a94b@syzkaller.appspotmail.com > Signed-off-by: Shakeel Butt <shakeelb@google.com> > --- > Changelog since v2: > - Further divided the patch into two patches. > - More cleaned version. > > Changelog since v1: > - Divide the patch into two patches. Acked-by: Roman Gushchin <guro@fb.com> for the series. Thanks, Shakeel! ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2019-06-28 2:17 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-06-24 21:26 [PATCH v3 1/3] mm, oom: refactor dump_tasks for memcg OOMs Shakeel Butt 2019-06-24 21:26 ` [PATCH v3 2/3] mm, oom: remove redundant task_in_mem_cgroup() check Shakeel Butt 2019-06-26 6:38 ` Michal Hocko 2019-06-28 2:12 ` Shakeel Butt 2019-06-24 21:26 ` [PATCH v3 3/3] oom: decouple mems_allowed from oom_unkillable_task Shakeel Butt 2019-06-26 6:55 ` Michal Hocko 2019-06-28 2:17 ` Shakeel Butt 2019-06-26 9:18 ` Michal Hocko 2019-06-26 19:47 ` Roman Gushchin
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