From d823445b09a2f1c43877b87a55fc699c3a836fc2 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Tue, 1 Aug 2023 15:32:50 +0300 Subject: [PATCH] drm/i915/uncore: fix race around i915->params.mmio_debug Only check the conditions for unclaimed reg debug once to avoid locking problems when i915->params.mmio_debug changes between header and footer. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8749 Cc: Lee Shawn C Reviewed-by: Tvrtko Ursulin Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/a53fb0fd84c4627398ccd4304b35db05603b89b6.1690886109.git.jani.nikula@intel.com --- drivers/gpu/drm/i915/intel_uncore.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index a88aa34..dfefad5 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1925,27 +1925,26 @@ __unclaimed_previous_reg_debug(struct intel_uncore *uncore, i915_mmio_reg_offset(reg)); } -static inline void +static inline bool __must_check unclaimed_reg_debug_header(struct intel_uncore *uncore, const i915_reg_t reg, const bool read) { if (likely(!uncore->i915->params.mmio_debug) || !uncore->debug) - return; + return false; /* interrupts are disabled and re-enabled around uncore->lock usage */ lockdep_assert_held(&uncore->lock); spin_lock(&uncore->debug->lock); __unclaimed_previous_reg_debug(uncore, reg, read); + + return true; } static inline void unclaimed_reg_debug_footer(struct intel_uncore *uncore, const i915_reg_t reg, const bool read) { - if (likely(!uncore->i915->params.mmio_debug) || !uncore->debug) - return; - /* interrupts are disabled and re-enabled around uncore->lock usage */ lockdep_assert_held(&uncore->lock); @@ -2008,13 +2007,15 @@ __gen2_read(64) #define GEN6_READ_HEADER(x) \ u32 offset = i915_mmio_reg_offset(reg); \ unsigned long irqflags; \ + bool unclaimed_reg_debug; \ u##x val = 0; \ assert_rpm_wakelock_held(uncore->rpm); \ spin_lock_irqsave(&uncore->lock, irqflags); \ - unclaimed_reg_debug_header(uncore, reg, true) + unclaimed_reg_debug = unclaimed_reg_debug_header(uncore, reg, true) #define GEN6_READ_FOOTER \ - unclaimed_reg_debug_footer(uncore, reg, true); \ + if (unclaimed_reg_debug) \ + unclaimed_reg_debug_footer(uncore, reg, true); \ spin_unlock_irqrestore(&uncore->lock, irqflags); \ trace_i915_reg_rw(false, reg, val, sizeof(val), trace); \ return val @@ -2112,13 +2113,15 @@ __gen2_write(32) #define GEN6_WRITE_HEADER \ u32 offset = i915_mmio_reg_offset(reg); \ unsigned long irqflags; \ + bool unclaimed_reg_debug; \ trace_i915_reg_rw(true, reg, val, sizeof(val), trace); \ assert_rpm_wakelock_held(uncore->rpm); \ spin_lock_irqsave(&uncore->lock, irqflags); \ - unclaimed_reg_debug_header(uncore, reg, false) + unclaimed_reg_debug = unclaimed_reg_debug_header(uncore, reg, false) #define GEN6_WRITE_FOOTER \ - unclaimed_reg_debug_footer(uncore, reg, false); \ + if (unclaimed_reg_debug) \ + unclaimed_reg_debug_footer(uncore, reg, false); \ spin_unlock_irqrestore(&uncore->lock, irqflags) #define __gen6_write(x) \ -- 2.7.4