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authorChris Wilson <chris@chris-wilson.co.uk>2013-09-20 10:20:59 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-09-24 09:36:40 +0200
commite29bb4ebbf000ff9ac081d29784a3331618f012e (patch)
treecb65cef4276e592094d59388e76f2039f15b8b77 /drivers/gpu/drm/i915/i915_gpu_error.c
parent4a10c2ac2f368583138b774ca41fac4207911983 (diff)
downloadlinaro-lsk-e29bb4ebbf000ff9ac081d29784a3331618f012e.tar.gz
drm/i915: Use a temporary va_list for two-pass string handling
In commit edc3d8848dc9fe2a470316363dab8ef211d77e01 Author: Mika Kuoppala <mika.kuoppala@linux.intel.com> Date: Thu May 23 13:55:35 2013 +0300 drm/i915: avoid big kmallocs on reading error state we introduce a two-pass mechanism for splitting long strings being formatted into the error-state. The first pass finds the length, and the second pass emits the right portion of the string into the accumulation buffer. Unfortunately we use the same va_list for both passes, resulting in the second pass reading garbage off the end of the argument list. As the two passes are only used for boundaries between read() calls, the corruption is only rarely seen. This fixes the root cause behind commit baf27f9b17bf2f369f3865e38c41d2163e8d815d Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Sat Jun 29 23:26:50 2013 +0100 drm/i915: Break up the large vsnprintf() in print_error_buffers() Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gpu_error.c')
-rw-r--r--drivers/gpu/drm/i915/i915_gpu_error.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index aba9d749899..dae364f0028 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -143,8 +143,10 @@ static void i915_error_vprintf(struct drm_i915_error_state_buf *e,
/* Seek the first printf which is hits start position */
if (e->pos < e->start) {
- len = vsnprintf(NULL, 0, f, args);
- if (!__i915_error_seek(e, len))
+ va_list tmp;
+
+ va_copy(tmp, args);
+ if (!__i915_error_seek(e, vsnprintf(NULL, 0, f, tmp)))
return;
}