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drm/i915: Break up the large vsnprintf() in print_error_buffers() 

So it appears that I have encountered some bogosity when trying to call
i915_error_printf() with many arguments from print_error_buffers(). The
symptom is that the vsnprintf parser tries to interpret an integer arg
as a character string, the resulting OOPS indicating stack corruption.
Replacing the single call with its 13 format specifiers and arguments
with multiple calls to i915_error_printf() worked fine. This patch goes
one step further and introduced i915_error_puts() to pass the strings
simply.

It may not fix the root cause, but it does prevent my box from dying and
I think helps make print_error_buffers() more friendly.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66077
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
hifive-unleashed-5.1
Chris Wilson 2013-06-29 23:26:50 +01:00 committed by Daniel Vetter
parent d26e3af842
commit baf27f9b17
1 changed files with 79 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

109
drivers/gpu/drm/i915/i915_debugfs.c
View File

@ -647,41 +647,44 @@ static const char *purgeable_flag(int purgeable)
return purgeable ? " purgeable" : "";
}
static void i915_error_vprintf(struct drm_i915_error_state_buf *e,
const char *f, va_list args)
static bool __i915_error_ok(struct drm_i915_error_state_buf *e)
{
unsigned len;
if (!e->err && WARN(e->bytes > (e->size - 1), "overflow")) {
e->err = -ENOSPC;
return;
return false;
}
if (e->bytes == e->size - 1 || e->err)
return;
return false;
/* Seek the first printf which is hits start position */
if (e->pos < e->start) {
len = vsnprintf(NULL, 0, f, args);
if (e->pos + len <= e->start) {
e->pos += len;
return;
}
return true;
}
/* First vsnprintf needs to fit in full for memmove*/
if (len >= e->size) {
e->err = -EIO;
return;
}
static bool __i915_error_seek(struct drm_i915_error_state_buf *e,
unsigned len)
{
if (e->pos + len <= e->start) {
e->pos += len;
return false;
}
len = vsnprintf(e->buf + e->bytes, e->size - e->bytes, f, args);
if (len >= e->size - e->bytes)
len = e->size - e->bytes - 1;
/* First vsnprintf needs to fit in its entirety for memmove */
if (len >= e->size) {
e->err = -EIO;
return false;
}
return true;
}
static void __i915_error_advance(struct drm_i915_error_state_buf *e,
unsigned len)
{
/* If this is first printf in this window, adjust it so that
* start position matches start of the buffer
*/
if (e->pos < e->start) {
const size_t off = e->start - e->pos;
@ -701,6 +704,51 @@ static void i915_error_vprintf(struct drm_i915_error_state_buf *e,
e->pos += len;
}
static void i915_error_vprintf(struct drm_i915_error_state_buf *e,
const char *f, va_list args)
{
unsigned len;
if (!__i915_error_ok(e))
return;
/* 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))
return;
}
len = vsnprintf(e->buf + e->bytes, e->size - e->bytes, f, args);
if (len >= e->size - e->bytes)
len = e->size - e->bytes - 1;
__i915_error_advance(e, len);
}
static void i915_error_puts(struct drm_i915_error_state_buf *e,
const char *str)
{
unsigned len;
if (!__i915_error_ok(e))
return;
len = strlen(str);
/* Seek the first printf which is hits start position */
if (e->pos < e->start) {
if (!__i915_error_seek(e, len))
return;
}
if (len >= e->size - e->bytes)
len = e->size - e->bytes - 1;
memcpy(e->buf + e->bytes, str, len);
__i915_error_advance(e, len);
}
void i915_error_printf(struct drm_i915_error_state_buf *e, const char *f, ...)
{
va_list args;
@ -711,6 +759,7 @@ void i915_error_printf(struct drm_i915_error_state_buf *e, const char *f, ...)
}
#define err_printf(e, ...) i915_error_printf(e, __VA_ARGS__)
#define err_puts(e, s) i915_error_puts(e, s)
static void print_error_buffers(struct drm_i915_error_state_buf *m,
const char *name,
@ -720,26 +769,26 @@ static void print_error_buffers(struct drm_i915_error_state_buf *m,
err_printf(m, "%s [%d]:\n", name, count);
while (count--) {
err_printf(m, " %08x %8u %02x %02x %x %x%s%s%s%s%s%s%s",
err_printf(m, " %08x %8u %02x %02x %x %x",
err->gtt_offset,
err->size,
err->read_domains,
err->write_domain,
err->rseqno, err->wseqno,
pin_flag(err->pinned),
tiling_flag(err->tiling),
dirty_flag(err->dirty),
purgeable_flag(err->purgeable),
err->ring != -1 ? " " : "",
ring_str(err->ring),
cache_level_str(err->cache_level));
err->rseqno, err->wseqno);
err_puts(m, pin_flag(err->pinned));
err_puts(m, tiling_flag(err->tiling));
err_puts(m, dirty_flag(err->dirty));
err_puts(m, purgeable_flag(err->purgeable));
err_puts(m, err->ring != -1 ? " " : "");
err_puts(m, ring_str(err->ring));
err_puts(m, cache_level_str(err->cache_level));
if (err->name)
err_printf(m, " (name: %d)", err->name);
if (err->fence_reg != I915_FENCE_REG_NONE)
err_printf(m, " (fence: %d)", err->fence_reg);
err_printf(m, "\n");
err_puts(m, "\n");
err++;
}
}