diff options
author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-15 12:50:53 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-15 12:50:53 +0200 |
commit | dec46bbe8704c7890eb4970d1ac16d67c8fad226 (patch) | |
tree | 63c60599e479002566fb32dff14b45e9113fc49b | |
parent | 5dd38f2978a93c88e36cdc6e5360a78307f5b83c (diff) | |
download | stable-queue-dec46bbe8704c7890eb4970d1ac16d67c8fad226.tar.gz |
6.1-stable patches
added patches:
drm-i915-vma-fix-uaf-on-destroy-against-retire-race.patch
-rw-r--r-- | queue-6.1/drm-i915-vma-fix-uaf-on-destroy-against-retire-race.patch | 202 | ||||
-rw-r--r-- | queue-6.1/series | 1 |
2 files changed, 203 insertions, 0 deletions
diff --git a/queue-6.1/drm-i915-vma-fix-uaf-on-destroy-against-retire-race.patch b/queue-6.1/drm-i915-vma-fix-uaf-on-destroy-against-retire-race.patch new file mode 100644 index 0000000000..fce802ef3f --- /dev/null +++ b/queue-6.1/drm-i915-vma-fix-uaf-on-destroy-against-retire-race.patch @@ -0,0 +1,202 @@ +From 0e45882ca829b26b915162e8e86dbb1095768e9e Mon Sep 17 00:00:00 2001 +From: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> +Date: Tue, 5 Mar 2024 15:35:06 +0100 +Subject: drm/i915/vma: Fix UAF on destroy against retire race +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +From: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> + +commit 0e45882ca829b26b915162e8e86dbb1095768e9e upstream. + +Object debugging tools were sporadically reporting illegal attempts to +free a still active i915 VMA object when parking a GT believed to be idle. + +[161.359441] ODEBUG: free active (active state 0) object: ffff88811643b958 object type: i915_active hint: __i915_vma_active+0x0/0x50 [i915] +[161.360082] WARNING: CPU: 5 PID: 276 at lib/debugobjects.c:514 debug_print_object+0x80/0xb0 +... +[161.360304] CPU: 5 PID: 276 Comm: kworker/5:2 Not tainted 6.5.0-rc1-CI_DRM_13375-g003f860e5577+ #1 +[161.360314] Hardware name: Intel Corporation Rocket Lake Client Platform/RocketLake S UDIMM 6L RVP, BIOS RKLSFWI1.R00.3173.A03.2204210138 04/21/2022 +[161.360322] Workqueue: i915-unordered __intel_wakeref_put_work [i915] +[161.360592] RIP: 0010:debug_print_object+0x80/0xb0 +... +[161.361347] debug_object_free+0xeb/0x110 +[161.361362] i915_active_fini+0x14/0x130 [i915] +[161.361866] release_references+0xfe/0x1f0 [i915] +[161.362543] i915_vma_parked+0x1db/0x380 [i915] +[161.363129] __gt_park+0x121/0x230 [i915] +[161.363515] ____intel_wakeref_put_last+0x1f/0x70 [i915] + +That has been tracked down to be happening when another thread is +deactivating the VMA inside __active_retire() helper, after the VMA's +active counter has been already decremented to 0, but before deactivation +of the VMA's object is reported to the object debugging tool. + +We could prevent from that race by serializing i915_active_fini() with +__active_retire() via ref->tree_lock, but that wouldn't stop the VMA from +being used, e.g. from __i915_vma_retire() called at the end of +__active_retire(), after that VMA has been already freed by a concurrent +i915_vma_destroy() on return from the i915_active_fini(). Then, we should +rather fix the issue at the VMA level, not in i915_active. + +Since __i915_vma_parked() is called from __gt_park() on last put of the +GT's wakeref, the issue could be addressed by holding the GT wakeref long +enough for __active_retire() to complete before that wakeref is released +and the GT parked. + +I believe the issue was introduced by commit d93939730347 ("drm/i915: +Remove the vma refcount") which moved a call to i915_active_fini() from +a dropped i915_vma_release(), called on last put of the removed VMA kref, +to i915_vma_parked() processing path called on last put of a GT wakeref. +However, its visibility to the object debugging tool was suppressed by a +bug in i915_active that was fixed two weeks later with commit e92eb246feb9 +("drm/i915/active: Fix missing debug object activation"). + +A VMA associated with a request doesn't acquire a GT wakeref by itself. +Instead, it depends on a wakeref held directly by the request's active +intel_context for a GT associated with its VM, and indirectly on that +intel_context's engine wakeref if the engine belongs to the same GT as the +VMA's VM. Those wakerefs are released asynchronously to VMA deactivation. + +Fix the issue by getting a wakeref for the VMA's GT when activating it, +and putting that wakeref only after the VMA is deactivated. However, +exclude global GTT from that processing path, otherwise the GPU never goes +idle. Since __i915_vma_retire() may be called from atomic contexts, use +async variant of wakeref put. Also, to avoid circular locking dependency, +take care of acquiring the wakeref before VM mutex when both are needed. + +v7: Add inline comments with justifications for: + - using untracked variants of intel_gt_pm_get/put() (Nirmoy), + - using async variant of _put(), + - not getting the wakeref in case of a global GTT, + - always getting the first wakeref outside vm->mutex. +v6: Since __i915_vma_active/retire() callbacks are not serialized, storing + a wakeref tracking handle inside struct i915_vma is not safe, and + there is no other good place for that. Use untracked variants of + intel_gt_pm_get/put_async(). +v5: Replace "tile" with "GT" across commit description (Rodrigo), + - avoid mentioning multi-GT case in commit description (Rodrigo), + - explain why we need to take a temporary wakeref unconditionally inside + i915_vma_pin_ww() (Rodrigo). +v4: Refresh on top of commit 5e4e06e4087e ("drm/i915: Track gt pm + wakerefs") (Andi), + - for more easy backporting, split out removal of former insufficient + workarounds and move them to separate patches (Nirmoy). + - clean up commit message and description a bit. +v3: Identify root cause more precisely, and a commit to blame, + - identify and drop former workarounds, + - update commit message and description. +v2: Get the wakeref before VM mutex to avoid circular locking dependency, + - drop questionable Fixes: tag. + +Fixes: d93939730347 ("drm/i915: Remove the vma refcount") +Closes: https://gitlab.freedesktop.org/drm/intel/issues/8875 +Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> +Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> +Cc: Nirmoy Das <nirmoy.das@intel.com> +Cc: Andi Shyti <andi.shyti@linux.intel.com> +Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> +Cc: stable@vger.kernel.org # v5.19+ +Reviewed-by: Nirmoy Das <nirmoy.das@intel.com> +Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com> +Link: https://patchwork.freedesktop.org/patch/msgid/20240305143747.335367-6-janusz.krzysztofik@linux.intel.com +(cherry picked from commit f3c71b2ded5c4367144a810ef25f998fd1d6c381) +Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> +Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + drivers/gpu/drm/i915/i915_vma.c | 50 ++++++++++++++++++++++++++++++++++------ + 1 file changed, 43 insertions(+), 7 deletions(-) + +--- a/drivers/gpu/drm/i915/i915_vma.c ++++ b/drivers/gpu/drm/i915/i915_vma.c +@@ -32,6 +32,7 @@ + #include "gt/intel_engine.h" + #include "gt/intel_engine_heartbeat.h" + #include "gt/intel_gt.h" ++#include "gt/intel_gt_pm.h" + #include "gt/intel_gt_requests.h" + + #include "i915_drv.h" +@@ -98,12 +99,42 @@ static inline struct i915_vma *active_to + + static int __i915_vma_active(struct i915_active *ref) + { +- return i915_vma_tryget(active_to_vma(ref)) ? 0 : -ENOENT; ++ struct i915_vma *vma = active_to_vma(ref); ++ ++ if (!i915_vma_tryget(vma)) ++ return -ENOENT; ++ ++ /* ++ * Exclude global GTT VMA from holding a GT wakeref ++ * while active, otherwise GPU never goes idle. ++ */ ++ if (!i915_vma_is_ggtt(vma)) { ++ /* ++ * Since we and our _retire() counterpart can be ++ * called asynchronously, storing a wakeref tracking ++ * handle inside struct i915_vma is not safe, and ++ * there is no other good place for that. Hence, ++ * use untracked variants of intel_gt_pm_get/put(). ++ */ ++ intel_gt_pm_get_untracked(vma->vm->gt); ++ } ++ ++ return 0; + } + + static void __i915_vma_retire(struct i915_active *ref) + { +- i915_vma_put(active_to_vma(ref)); ++ struct i915_vma *vma = active_to_vma(ref); ++ ++ if (!i915_vma_is_ggtt(vma)) { ++ /* ++ * Since we can be called from atomic contexts, ++ * use an async variant of intel_gt_pm_put(). ++ */ ++ intel_gt_pm_put_async_untracked(vma->vm->gt); ++ } ++ ++ i915_vma_put(vma); + } + + static struct i915_vma * +@@ -1365,7 +1396,7 @@ int i915_vma_pin_ww(struct i915_vma *vma + struct i915_vma_work *work = NULL; + struct dma_fence *moving = NULL; + struct i915_vma_resource *vma_res = NULL; +- intel_wakeref_t wakeref = 0; ++ intel_wakeref_t wakeref; + unsigned int bound; + int err; + +@@ -1385,8 +1416,14 @@ int i915_vma_pin_ww(struct i915_vma *vma + if (err) + return err; + +- if (flags & PIN_GLOBAL) +- wakeref = intel_runtime_pm_get(&vma->vm->i915->runtime_pm); ++ /* ++ * In case of a global GTT, we must hold a runtime-pm wakeref ++ * while global PTEs are updated. In other cases, we hold ++ * the rpm reference while the VMA is active. Since runtime ++ * resume may require allocations, which are forbidden inside ++ * vm->mutex, get the first rpm wakeref outside of the mutex. ++ */ ++ wakeref = intel_runtime_pm_get(&vma->vm->i915->runtime_pm); + + if (flags & vma->vm->bind_async_flags) { + /* lock VM */ +@@ -1522,8 +1559,7 @@ err_fence: + if (work) + dma_fence_work_commit_imm(&work->base); + err_rpm: +- if (wakeref) +- intel_runtime_pm_put(&vma->vm->i915->runtime_pm, wakeref); ++ intel_runtime_pm_put(&vma->vm->i915->runtime_pm, wakeref); + + if (moving) + dma_fence_put(moving); diff --git a/queue-6.1/series b/queue-6.1/series index 564a01432f..65148b1520 100644 --- a/queue-6.1/series +++ b/queue-6.1/series @@ -39,3 +39,4 @@ net-ena-fix-incorrect-descriptor-free-behavior.patch tracing-fix-ftrace_record_recursion_size-kconfig-ent.patch tracing-hide-unused-ftrace_event_id_fops.patch iommu-vt-d-allocate-local-memory-for-page-request-qu.patch +drm-i915-vma-fix-uaf-on-destroy-against-retire-race.patch |