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16d51a590a
When going through execve(), zero out the NUMA fault statistics instead of
freeing them.
During execve, the task is reachable through procfs and the scheduler. A
concurrent /proc/*/sched reader can read data from a freed ->numa_faults
allocation (confirmed by KASAN) and write it back to userspace.
I believe that it would also be possible for a use-after-free read to occur
through a race between a NUMA fault and execve(): task_numa_fault() can
lead to task_numa_compare(), which invokes task_weight() on the currently
running task of a different CPU.
Another way to fix this would be to make ->numa_faults RCU-managed or add
extra locking, but it seems easier to wipe the NUMA fault statistics on
execve.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Fixes: 82727018b0 ("sched/numa: Call task_numa_free() from do_execve()")
Link: https://lkml.kernel.org/r/20190716152047.14424-1-jannh@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_NUMA_BALANCING_H
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#define _LINUX_SCHED_NUMA_BALANCING_H
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/*
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* This is the interface between the scheduler and the MM that
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* implements memory access pattern based NUMA-balancing:
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*/
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#include <linux/sched.h>
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#define TNF_MIGRATED 0x01
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#define TNF_NO_GROUP 0x02
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#define TNF_SHARED 0x04
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#define TNF_FAULT_LOCAL 0x08
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#define TNF_MIGRATE_FAIL 0x10
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#ifdef CONFIG_NUMA_BALANCING
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extern void task_numa_fault(int last_node, int node, int pages, int flags);
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extern pid_t task_numa_group_id(struct task_struct *p);
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extern void set_numabalancing_state(bool enabled);
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extern void task_numa_free(struct task_struct *p, bool final);
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extern bool should_numa_migrate_memory(struct task_struct *p, struct page *page,
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int src_nid, int dst_cpu);
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#else
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static inline void task_numa_fault(int last_node, int node, int pages,
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int flags)
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{
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}
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static inline pid_t task_numa_group_id(struct task_struct *p)
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{
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return 0;
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}
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static inline void set_numabalancing_state(bool enabled)
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{
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}
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static inline void task_numa_free(struct task_struct *p, bool final)
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{
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}
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static inline bool should_numa_migrate_memory(struct task_struct *p,
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struct page *page, int src_nid, int dst_cpu)
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{
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return true;
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}
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#endif
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#endif /* _LINUX_SCHED_NUMA_BALANCING_H */
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