The patch titled
Subject: sched_show_task: fix unsafe usage of ->real_parent
has been removed from the -mm tree. Its filename was
sched_show_task-fix-unsafe-usage-of-real_parent.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: sched_show_task: fix unsafe usage of ->real_parent
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.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Aaron Tomlin <atomlin@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>,
Cc: Sterling Alexander <stalexan@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sched/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff -puN kernel/sched/core.c~sched_show_task-fix-unsafe-usage-of-real_parent kernel/sched/core.c
--- a/kernel/sched/core.c~sched_show_task-fix-unsafe-usage-of-real_parent
+++ a/kernel/sched/core.c
@@ -4527,8 +4527,10 @@ void sched_show_task(struct task_struct
#ifdef CONFIG_DEBUG_STACK_USAGE
free = stack_not_used(p);
#endif
+ ppid = 0;
rcu_read_lock();
- ppid = task_pid_nr(rcu_dereference(p->real_parent));
+ if (pid_alive(p))
+ ppid = task_pid_nr(rcu_dereference(p->real_parent));
rcu_read_unlock();
printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
task_pid_nr(p), ppid,
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
mmfs-introduce-helpers-around-the-i_mmap_mutex.patch
mm-use-new-helper-functions-around-the-i_mmap_mutex.patch
mm-convert-i_mmap_mutex-to-rwsem.patch
mm-rmap-share-the-i_mmap_rwsem.patch
uprobes-share-the-i_mmap_rwsem.patch
mm-xip-share-the-i_mmap_rwsem.patch
mm-memory-failure-share-the-i_mmap_rwsem.patch
mm-nommu-share-the-i_mmap_rwsem.patch
mm-memoryc-share-the-i_mmap_rwsem.patch
remove-unnecessary-is_valid_nodemask.patch
oom-dont-assume-that-a-coredumping-thread-will-exit-soon.patch
oom-dont-assume-that-a-coredumping-thread-will-exit-soon-v2.patch
oom-dont-assume-that-a-coredumping-thread-will-exit-soon-v2-fix.patch
oom-kill-the-insufficient-and-no-longer-needed-pt_trace_exit-check.patch
linux-next.patch
all-arches-signal-move-restart_block-to-struct-task_struct.patch
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