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 at chris-wilson.co.uk> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66077 Cc: Mika Kuoppala <mika.kuoppala at intel.com> --- drivers/gpu/drm/i915/i915_debugfs.c | 109 ++++++++++++++++++++++++++---------- 1 file changed, 79 insertions(+), 30 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 55c89af..7eae6b0 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -650,41 +650,44 @@ 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; @@ -704,6 +707,51 @@ 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; @@ -714,6 +762,7 @@ 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, @@ -723,26 +772,26 @@ 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++; } } -- 1.8.3.1
