From: Vikram Mulukutla <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 7215853e985a4bef1a6c14e00e89dfec84f1e457 upstream. Commit 6edb2a8a385f0cdef51dae37ff23e74d76d8a6ce introduced an array map_pages that contains the addresses returned by kmap_atomic. However, when unmapping those pages, map_pages[0] is unmapped before map_pages[1], breaking the nesting requirement as specified in the documentation for kmap_atomic/kunmap_atomic. This was caught by the highmem debug code present in kunmap_atomic. Fix the loop to do the unmapping properly. Link: http://lkml.kernel.org/r/[email protected] Reviewed-by: Stephen Boyd <[email protected]> Reported-by: Lime Yang <[email protected]> Signed-off-by: Vikram Mulukutla <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 691a8ea6f472..1b51436db225 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4599,7 +4599,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, *fpos += written; out_unlock: - for (i = 0; i < nr_pages; i++){ + for (i = nr_pages - 1; i >= 0; i--) { kunmap_atomic(map_page[i]); put_page(pages[i]); } -- 2.3.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
