Re: [patch for-3.7 v3] mm, mempolicy: hold task->mempolicy refcount while reading numa_maps.
From: David Rientjes <rientjes@google.com>
Date: 2012-10-19 09:28:48
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On Fri, 19 Oct 2012, Kamezawa Hiroyuki wrote:
From c5849c9034abeec3f26bf30dadccd393b0c5c25e Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki <redacted> Date: Fri, 19 Oct 2012 17:00:55 +0900 Subject: [PATCH] hold task->mempolicy while numa_maps scans. /proc/<pid>/numa_maps scans vma and show mempolicy under mmap_sem. It sometimes accesses task->mempolicy which can be freed without mmap_sem and numa_maps can show some garbage while scanning. This patch tries to take reference count of task->mempolicy at reading numa_maps before calling get_vma_policy(). By this, task->mempolicy will not be freed until numa_maps reaches its end. Signed-off-by: KAMEZAWA Hiroyuki <redacted>
Looks good, but the patch is whitespace damaged so it doesn't apply. When that's fixed: Acked-by: David Rientjes <rientjes@google.com> Thanks for following through on this! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>