diff options
| author | David Gibson <david@gibson.dropbear.id.au> | 2005-11-29 19:46:37 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2005-12-14 15:42:54 -0800 |
| commit | d948e779d14768cee4077ad5b477d58d42b20371 (patch) | |
| tree | 67b71390cc71b6ab2c4c6d3594a4252cecbf23bd /kernel/ptrace.c | |
| parent | 2d6eac6c4fdaa69656d66c80754d267be233cc3f (diff) | |
[PATCH] Fix crash when ptrace poking hugepage areas
set_page_dirty() will not cope with being handed a page * which is part of
a compound page, but not the master page in that compound page. This case
can occur via access_process_vm() if you attemp to write to another
process's hugepage memory area using ptrace() (causing an oops or hang).
This patch fixes the bug by only calling set_page_dirty() from
access_process_vm() if the page is not a compound page. We already use a
similar fix in bio_set_pages_dirty() for the case of direct io to
hugepages.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel/ptrace.c')
| -rw-r--r-- | kernel/ptrace.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index fcfc4568b45..260165f0844 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -238,7 +238,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in if (write) { copy_to_user_page(vma, page, addr, maddr + offset, buf, bytes); - set_page_dirty_lock(page); + if (!PageCompound(page)) + set_page_dirty_lock(page); } else { copy_from_user_page(vma, page, addr, buf, maddr + offset, bytes); |