From 78ac1c3558810486d90aa533b0039aa70487a3da Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20K=C3=B6nig?= Date: Fri, 8 Nov 2024 09:29:48 +0100 Subject: [PATCH 1/3] dma-buf: fix dma_fence_array_signaled v4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The function silently assumed that signaling was already enabled for the dma_fence_array. This meant that without enabling signaling first we would never see forward progress. Fix that by falling back to testing each individual fence when signaling isn't enabled yet. v2: add the comment suggested by Boris why this is done this way v3: fix the underflow pointed out by Tvrtko v4: atomic_read_acquire() as suggested by Tvrtko Signed-off-by: Christian König Reviewed-by: Boris Brezillon Tested-by: Chia-I Wu Reviewed-by: Tvrtko Ursulin Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/12094 Cc: Link: https://patchwork.freedesktop.org/patch/msgid/20241112121925.18464-1-christian.koenig@amd.com --- drivers/dma-buf/dma-fence-array.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c index 8a08ffde31e7..6657d4b30af9 100644 --- a/drivers/dma-buf/dma-fence-array.c +++ b/drivers/dma-buf/dma-fence-array.c @@ -103,10 +103,36 @@ static bool dma_fence_array_enable_signaling(struct dma_fence *fence) static bool dma_fence_array_signaled(struct dma_fence *fence) { struct dma_fence_array *array = to_dma_fence_array(fence); + int num_pending; + unsigned int i; - if (atomic_read(&array->num_pending) > 0) + /* + * We need to read num_pending before checking the enable_signal bit + * to avoid racing with the enable_signaling() implementation, which + * might decrement the counter, and cause a partial check. + * atomic_read_acquire() pairs with atomic_dec_and_test() in + * dma_fence_array_enable_signaling() + * + * The !--num_pending check is here to account for the any_signaled case + * if we race with enable_signaling(), that means the !num_pending check + * in the is_signalling_enabled branch might be outdated (num_pending + * might have been decremented), but that's fine. The user will get the + * right value when testing again later. + */ + num_pending = atomic_read_acquire(&array->num_pending); + if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &array->base.flags)) { + if (num_pending <= 0) + goto signal; return false; + } + for (i = 0; i < array->num_fences; ++i) { + if (dma_fence_is_signaled(array->fences[i]) && !--num_pending) + goto signal; + } + return false; + +signal: dma_fence_array_clear_pending_error(array); return true; } From bd2fccac61b40eaf08d9546acc9fef958bfe4763 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Mon, 25 Nov 2024 22:53:14 +0200 Subject: [PATCH 2/3] drm/dp_mst: Fix MST sideband message body length check Fix the MST sideband message body length check, which must be at least 1 byte accounting for the message body CRC (aka message data CRC) at the end of the message. This fixes a case where an MST branch device returns a header with a correct header CRC (indicating a correctly received body length), with the body length being incorrectly set to 0. This will later lead to a memory corruption in drm_dp_sideband_append_payload() and the following errors in dmesg: UBSAN: array-index-out-of-bounds in drivers/gpu/drm/display/drm_dp_mst_topology.c:786:25 index -1 is out of range for type 'u8 [48]' Call Trace: drm_dp_sideband_append_payload+0x33d/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper] memcpy: detected field-spanning write (size 18446744073709551615) of single field "&msg->msg[msg->curlen]" at drivers/gpu/drm/display/drm_dp_mst_topology.c:791 (size 256) Call Trace: drm_dp_sideband_append_payload+0x324/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper] Cc: Cc: Lyude Paul Reviewed-by: Lyude Paul Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/20241125205314.1725887-1-imre.deak@intel.com --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index ac90118b9e7a..e6ee180815b2 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -320,6 +320,9 @@ static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr hdr->broadcast = (buf[idx] >> 7) & 0x1; hdr->path_msg = (buf[idx] >> 6) & 0x1; hdr->msg_len = buf[idx] & 0x3f; + if (hdr->msg_len < 1) /* min space for body CRC */ + return false; + idx++; hdr->somt = (buf[idx] >> 7) & 0x1; hdr->eomt = (buf[idx] >> 6) & 0x1; From 86e8f94789dd6f3e705bfa821e1e416f97a2f863 Mon Sep 17 00:00:00 2001 From: Pei Xiao Date: Wed, 20 Nov 2024 15:21:36 +0800 Subject: [PATCH 3/3] drm/sti: Add __iomem for mixer_dbg_mxn's parameter Sparse complains about incorrect type in argument 1. expected void const volatile __iomem *ptr but got void *. so modify mixer_dbg_mxn's addr parameter. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202411191809.6V3c826r-lkp@intel.com/ Fixes: a5f81078a56c ("drm/sti: add debugfs entries for MIXER crtc") Signed-off-by: Pei Xiao Acked-by: Raphael Gallais-Pou Link: https://patchwork.freedesktop.org/patch/msgid/c28f0dcb6a4526721d83ba1f659bba30564d3d54.1732087094.git.xiaopei01@kylinos.cn Signed-off-by: Raphael Gallais-Pou --- drivers/gpu/drm/sti/sti_mixer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/sti/sti_mixer.c b/drivers/gpu/drm/sti/sti_mixer.c index 7e5f14646625..06c1b81912f7 100644 --- a/drivers/gpu/drm/sti/sti_mixer.c +++ b/drivers/gpu/drm/sti/sti_mixer.c @@ -137,7 +137,7 @@ static void mixer_dbg_crb(struct seq_file *s, int val) } } -static void mixer_dbg_mxn(struct seq_file *s, void *addr) +static void mixer_dbg_mxn(struct seq_file *s, void __iomem *addr) { int i;