diff options
| author | Andy Lutomirski <luto@kernel.org> | 2016-09-30 10:58:57 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-11-20 18:05:58 +0000 |
| commit | 116d8eebbd21c3f011240d3f3f9195c6ed0c42f6 (patch) | |
| tree | b5e15036ef98fb9bd024850f1fd953954f6efcc0 /include | |
| parent | 7a71d994ade5062ec16b64aaa5842d29db4f1700 (diff) | |
fs/proc: Stop trying to report thread stacks
commit b18cb64ead400c01bf1580eeba330ace51f8087d upstream.
This reverts more of:
b76437579d13 ("procfs: mark thread stack correctly in proc/<pid>/maps")
... which was partially reverted by:
65376df58217 ("proc: revert /proc/<pid>/maps [stack:TID] annotation")
Originally, /proc/PID/task/TID/maps was the same as /proc/TID/maps.
In current kernels, /proc/PID/maps (or /proc/TID/maps even for
threads) shows "[stack]" for VMAs in the mm's stack address range.
In contrast, /proc/PID/task/TID/maps uses KSTK_ESP to guess the
target thread's stack's VMA. This is racy, probably returns garbage
and, on arches with CONFIG_TASK_INFO_IN_THREAD=y, is also crash-prone:
KSTK_ESP is not safe to use on tasks that aren't known to be running
ordinary process-context kernel code.
This patch removes the difference and just shows "[stack]" for VMAs
in the mm's stack range. This is IMO much more sensible -- the
actual "stack" address really is treated specially by the VM code,
and the current thread stack isn't even well-defined for programs
that frequently switch stacks on their own.
Reported-by: Jann Horn <jann@thejh.net>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux API <linux-api@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tycho Andersen <tycho.andersen@canonical.com>
Link: http://lkml.kernel.org/r/3e678474ec14e0a0ec34c611016753eea2e1b8ba.1475257877.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.16: Squash in the earlier commits 58cb65487e92
"proc/maps: make vm_is_stack() logic namespace-friendly" and
65376df58217 "proc: revert /proc/<pid>/maps [stack:TID] annotation",
which would introduce build failures if applied separately.]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 1ecb0d0e56ec..a93a36e1a480 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1239,8 +1239,7 @@ int set_page_dirty_lock(struct page *page); int clear_page_dirty_for_io(struct page *page); int get_cmdline(struct task_struct *task, char *buffer, int buflen); -extern pid_t -vm_is_stack(struct task_struct *task, struct vm_area_struct *vma, int in_group); +int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t); extern unsigned long move_page_tables(struct vm_area_struct *vma, unsigned long old_addr, struct vm_area_struct *new_vma, |