- Jan 13, 2022
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Fix cma_heap_buffer mutex locking critical section to protect vmap_cnt and vaddr. Fixes: a5d2d29e ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation") Signed-off-by:
Weizhao Ouyang <o451686892@gmail.com> Acked-by:
John Stultz <john.stultz@linaro.org> Signed-off-by:
Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20220104073545.124244-1-o451686892@gmail.com
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- Dec 01, 2021
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For previous version, it uses 'sg_table.nent's to traverse sg_table in pages free flow. However, 'sg_table.nents' is reassigned in 'dma_map_sg', it means the number of created entries in the DMA adderess space. So, use 'sg_table.nents' in pages free flow will case some pages can't be freed. Here we should use sg_table.orig_nents to free pages memory, but use the sgtable helper 'for each_sgtable_sg'(, instead of the previous rather common helper 'for_each_sg' which maybe cause memory leak) is much better. Fixes: d963ab0f ("dma-buf: system_heap: Allocate higher order pages if available") Signed-off-by:
Guangming <Guangming.Cao@mediatek.com> Reviewed-by:
Robin Murphy <robin.murphy@arm.com> Cc: <stable@vger.kernel.org> # 5.11.* Reviewed-by:
Christian König <christian.koenig@amd.com> Reviewed-by:
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- Nov 30, 2021
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Christian König authored
Calling dma_resv_add_excl_fence() with the fence as NULL and expecting that that this frees up the fences is simply abuse of the internals of the dma_resv object. v2: drop the fence pruning completely. Signed-off-by:
Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20211129120659.1815-4-christian.koenig@amd.com
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Thomas Hellström authored
If a dma_fence_array is reported signaled by a call to dma_fence_is_signaled(), it may leak the PENDING_ERROR status. Fix this by clearing the PENDING_ERROR status if we return true in dma_fence_array_signaled(). v2: - Update Cc list, and add R-b. Fixes: 1f70b8b8 ("dma-fence: Propagate errors to dma-fence-array container") Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: Christian König <christian.koenig@amd.com> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: <stable@vger.kernel.org> # v5.4+ Signed-off-by:
Thomas Hellström <thomas.hellstrom@linux.intel.com> Reviewed-by:
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- Nov 11, 2021
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Christian König authored
Add functions to dump dma_fence and dma_resv objects into a seq_file and use them for printing the debugfs information. v2: fix missing include reported by test robot. Signed-off-by:
Rob Clark <robdclark@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20211103081231.18578-2-christian.koenig@amd.com
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- Nov 04, 2021
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This makes sure we don't hit the BUG_ON(dmabuf->cb_in.active || dmabuf->cb_out.active); in dma_buf_release, which could be triggered by user space closing the dma-buf file description while there are outstanding fence callbacks from dma_buf_poll. Cc: stable@vger.kernel.org Signed-off-by:
Michel Dänzer <mdaenzer@redhat.com> Reviewed-by:
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- Oct 29, 2021
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Because dma-buf.name can be freed in func: "dma_buf_set_name", so, we need to acquire lock first before we read/write dma_buf.name to prevent Use After Free(UAF) issue. Signed-off-by:
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- Oct 28, 2021
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In this patch(https://patchwork.freedesktop.org/patch/310349), it add a new IOCTL to support dma-buf user to set debug name. But it also added a limitation of this IOCTL, it needs the attachments of dmabuf should be empty, otherwise it will fail. For the original series, the idea was that allowing name change mid-use could confuse the users about the dma-buf. However, the rest of the series also makes sure each dma-buf have a unique inode(https://patchwork.freedesktop.org/patch/310387/ ), and any accounting should probably use that, without relying on the name as much. So, removing this restriction will let dma-buf userspace users to use it more comfortably and without any side effect. Signed-off-by:
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- Oct 26, 2021
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The new driver incorrectly unwinds after errors, as clang points out: drivers/dma-buf/st-dma-resv.c:295:7: error: variable 'i' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (r) { ^ drivers/dma-buf/st-dma-resv.c:336:9: note: uninitialized use occurs here while (i--) ^ drivers/dma-buf/st-dma-resv.c:295:3: note: remove the 'if' if its condition is always false if (r) { ^~~~~~~~ drivers/dma-buf/st-dma-resv.c:288:6: error: variable 'i' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (r) { ^ drivers/dma-buf/st-dma-resv.c:336:9: note: uninitialized use occurs here while (i--) ^ drivers/dma-buf/st-dma-resv.c:288:2: note: remove the 'if' if its condition is always false if (r) { ^~~~~~~~ drivers/dma-buf/st-dma-resv.c:280:10: note: initialize the variable 'i' to silence this warning int r, i; ^ = 0 Skip cleaning up the bits that have not been allocated at this point. Fixes: 1d51775c ("dma-buf: add dma_resv selftest v4") Signed-off-by:Arnd Bergmann <arnd@arndb.de> Reviewed-by:
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- Oct 25, 2021
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Greg Kroah-Hartman authored
In order to better track where in the kernel the dma-buf code is used, put the symbols in the namespace DMA_BUF and modify all users of the symbols to properly import the namespace to not break the build at the same time. Now the output of modinfo shows the use of these symbols, making it easier to watch for users over time: $ modinfo drivers/misc/fastrpc.ko | grep import import_ns: DMA_BUF Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: dri-devel@lists.freedesktop.org Acked-by:
Alex Deucher <alexander.deucher@amd.com> Link: https://lore.kernel.org/r/20211010124628.17691-1-gregkh@linuxfoundation.org Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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- Oct 22, 2021
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Christian König authored
Just exercising a very minor subset of the functionality, but already proven useful. v2: add missing locking v3: some more cleanup and consolidation, add unlocked test as well v4: add a dma_resv_get_fences selftest Signed-off-by:
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- Oct 18, 2021
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A comment for the dma_buf_vmap/vunmap() is not catching up a corresponding implementation. Signed-off-by:
Shunsuke Mie <mie@igel.co.jp> Link: https://patchwork.freedesktop.org/patch/msgid/20211008112009.118996-1-mie@igel.co.jp Reviewed-by:
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- Oct 11, 2021
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Cache the count of shared fences in the iterator to avoid dereferencing the dma_resv_object outside the RCU protection. Otherwise iterator and its users can observe an incosistent state which makes it impossible to use safely. Such as: <6> [187.517041] [IGT] gem_sync: executing <7> [187.536343] i915 0000:00:02.0: [drm:i915_gem_context_create_ioctl [i915]] HW context 1 created <7> [187.536793] i915 0000:00:02.0: [drm:i915_gem_context_create_ioctl [i915]] HW context 1 created <6> [187.551235] [IGT] gem_sync: starting subtest basic-many-each <1> [188.935462] BUG: kernel NULL pointer dereference, address: 0000000000000010 <1> [188.935485] #PF: supervisor write access in kernel mode <1> [188.935495] #PF: error_code(0x0002) - not-present page <6> [188.935504] PGD 0 P4D 0 <4> [188.935512] Oops: 0002 [#1] PREEMPT SMP NOPTI <4> [188.935521] CPU: 2 PID: 1467 Comm: gem_sync Not tainted 5.15.0-rc4-CI-Patchwork_21264+ #1 <4> [188.935535] Hardware name: /NUC6CAYB, BIOS AYAPLCEL.86A.0049.2018.0508.1356 05/08/2018 <4> [188.935546] RIP: 0010:dma_resv_get_fences+0x116/0x2d0 <4> [188.935560] Code: 10 85 c0 7f c9 be 03 00 00 00 e8 15 8b df ff eb bd e8 8e c6 ff ff eb b6 41 8b 04 24 49 8b 55 00 48 89 e7 8d 48 01 41 89 0c 24 <4c> 89 34 c2 e8 41 f2 ff ff 49 89 c6 48 85 c0 75 8c 48 8b 44 24 10 <4> [188.935583] RSP: 0018:ffffc900011dbcc8 EFLAGS: 00010202 <4> [188.935593] RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000001 <4> [188.935603] RDX: 0000000000000010 RSI: ffffffff822e343c RDI: ffffc900011dbcc8 <4> [188.935613] RBP: ffffc900011dbd48 R08: ffff88812d255bb8 R09: 00000000fffffffe <4> [188.935623] R10: 0000000000000001 R11: 0000000000000000 R12: ffffc900011dbd44 <4> [188.935633] R13: ffffc900011dbd50 R14: ffff888113d29cc0 R15: 0000000000000000 <4> [188.935643] FS: 00007f68d17e9700(0000) GS:ffff888277900000(0000) knlGS:0000000000000000 <4> [188.935655] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> [188.935665] CR2: 0000000000000010 CR3: 000000012d0a4000 CR4: 00000000003506e0 <4> [188.935676] Call Trace: <4> [188.935685] i915_gem_object_wait+0x1ff/0x410 [i915] <4> [188.935988] i915_gem_wait_ioctl+0xf2/0x2a0 [i915] <4> [188.936272] ? i915_gem_object_wait+0x410/0x410 [i915] <4> [188.936533] drm_ioctl_kernel+0xae/0x140 <4> [188.936546] drm_ioctl+0x201/0x3d0 <4> [188.936555] ? i915_gem_object_wait+0x410/0x410 [i915] <4> [188.936820] ? __fget_files+0xc2/0x1c0 <4> [188.936830] ? __fget_files+0xda/0x1c0 <4> [188.936839] __x64_sys_ioctl+0x6d/0xa0 <4> [188.936848] do_syscall_64+0x3a/0xb0 <4> [188.936859] entry_SYSCALL_64_after_hwframe+0x44/0xae If the shared object has changed during the RCU unlocked period callers will correctly handle the restart on the next iteration. Signed-off-by:
Tvrtko Ursulin <tvrtko.ursulin@intel.com> Fixes: 96601e8a ("dma-buf: use new iterator in dma_resv_copy_fences") Fixes: d3c80698 ("dma-buf: use new iterator in dma_resv_get_fences v3") Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4274 Cc: Christian König <christian.koenig@amd.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20211008095007.972693-1-tvrtko.ursulin@linux.intel.com Reviewed-by:
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- Oct 07, 2021
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Christian König authored
Simplify the code a bit. Signed-off-by:
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Christian König authored
Simplifying the code a bit. Signed-off-by:
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Christian König authored
A simpler version of the iterator to be used when the dma_resv object is locked. v2: fix index check here as well v3: minor coding improvement, some documentation cleanup Signed-off-by:
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- Oct 06, 2021
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Christian König authored
This makes the function much simpler since the complex retry logic is now handled elsewhere. Signed-off-by:
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Christian König authored
This makes the function much simpler since the complex retry logic is now handled elsewhere. Signed-off-by:
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Christian König authored
This makes the function much simpler since the complex retry logic is now handled elsewhere. v2: use sizeof(void*) instead v3: fix rebase bug Signed-off-by:
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Christian König authored
This makes the function much simpler since the complex retry logic is now handled else where. Signed-off-by:
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Christian König authored
Abstract the complexity of iterating over all the fences in a dma_resv object. The new loop handles the whole RCU and retry dance and returns only fences where we can be sure we grabbed the right one. v2: fix accessing the shared fences while they might be freed, improve kerneldoc, rename _cursor to _iter, add dma_resv_iter_is_exclusive, add dma_resv_iter_begin/end v3: restructor the code, move rcu_read_lock()/unlock() into the iterator, add dma_resv_iter_is_restarted() v4: fix NULL deref when no explicit fence exists, drop superflous rcu_read_lock()/unlock() calls. v5: fix typos in the documentation v6: fix coding error when excl fence is NULL v7: one more logic fix v8: fix index check in dma_resv_iter_is_exclusive() Signed-off-by:
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- Oct 01, 2021
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Christian König authored
Daniel pointed me towards this function and there are multiple obvious problems in the implementation. First of all the retry loop is not working as intended. In general the retry makes only sense if you grab the reference first and then check the sequence values. Then we should always also wait for the exclusive fence. It's also good practice to keep the reference around when installing callbacks to fences you don't own. And last the whole implementation was unnecessary complex and rather hard to understand which could lead to probably unexpected behavior of the IOCTL. Fix all this by reworking the implementation from scratch. Dropping the whole RCU approach and taking the lock instead. Only mildly tested and needs a thoughtful review of the code. Pushing through drm-misc-next to avoid merge conflicts and give the code another round of testing. v2: fix the reference counting as well v3: keep the excl fence handling as is for stable v4: back to testing all fences, drop RCU v5: handle in and out separately v6: add missing clear of events v7: change coding style as suggested by Michel, drop unused variables Signed-off-by:
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- Sep 14, 2021
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When trying to do mid-order allocations, set __GFP_NOWARN to avoid warning messages if the allocation fails, as we will still fall back to single page allocatitions in that case. This is the similar to what we already do for large order allocations. Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Christian Koenig <christian.koenig@amd.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Liam Mark <lmark@codeaurora.org> Cc: Chris Goldsworthy <cgoldswo@codeaurora.org> Cc: Laura Abbott <labbott@kernel.org> Cc: Brian Starkey <Brian.Starkey@arm.com> Cc: Hridya Valsaraju <hridya@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sandeep Patil <sspatil@google.com> Cc: Daniel Mentz <danielmentz@google.com> Cc: Ørjan Eide <orjan.eide@arm.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Simon Ser <contact@emersion.fr> Cc: James Jones <jajones@nvidia.com> Cc: Leo Yan <leo.yan@linaro.org> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Signed-off-by:
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- Sep 07, 2021
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DMA-BUF sysfs statistics are an option of DMA-BUF. It does not make much sense to bother the user with a question about DMA-BUF sysfs statistics if DMA-BUF itself is not enabled. Worse, enabling the statistics enables the feature. Fixes: bdb8d06d ("dmabuf: Add the capability to expose DMA-BUF stats in sysfs") Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:
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DMA-BUF debug checks are an option of DMA-BUF. Enabling DMABUF_DEBUG without DMA_SHARED_BUFFER does not have any impact, as drivers/dma-buf/ is not entered during the build when DMA_SHARED_BUFFER is disabled. Fixes: 84335675 ("dma-buf: Add debug option") Signed-off-by:
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- Sep 03, 2021
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Christian König authored
That the caller doesn't need to keep a reference is rather risky and not defensive at all. Especially dma_buf_poll got that horrible wrong, so better remove that sentence and also clarify that the callback might be called in atomic or interrupt context. Signed-off-by:
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- Sep 02, 2021
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Move notify between drivers is an option of DMA-BUF. Enabling DMABUF_MOVE_NOTIFY without DMA_SHARED_BUFFER does not have any impact, as drivers/dma-buf/ is not entered during the build when DMA_SHARED_BUFFER is disabled. Fixes: bb42df46 ("dma-buf: add dynamic DMA-buf handling v15") Signed-off-by:
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- Aug 30, 2021
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Simona Vetter authored
Specifically document the new/clarified rules around how the shared fences do not have any ordering requirements against the exclusive fence. But also document all the things a bit better, given how central struct dma_resv to dynamic buffer management the docs have been very inadequat. - Lots more links to other pieces of the puzzle. Unfortunately ttm_buffer_object has no docs, so no links :-( - Explain/complain a bit about dma_resv_locking_ctx(). I still don't like that one, but fixing the ttm call chains is going to be horrible. Plus we want to plug in real slowpath locking when we do that anyway. - Main part of the patch is some actual docs for struct dma_resv. Overall I think we still have a lot of bad naming in this area (e.g. dma_resv.fence is singular, but contains the multiple shared fences), but I think that's more indicative of how the semantics and rules are just not great. Another thing that's real awkard is how chaining exclusive fences right now means direct dma_resv.exclusive_fence pointer access with an rcu_assign_pointer. Not so great either. v2: - Fix a pile of typos (Matt, Jason) - Hammer it in that breaking the rules leads to use-after-free issues around dma-buf sharing (Christian) Reviewed-by:
Matthew Auld <matthew.auld@intel.com> Signed-off-by:
Daniel Vetter <daniel.vetter@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
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- Aug 16, 2021
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It is expected from the clients to follow the below steps on an imported dmabuf fd: a) dmabuf = dma_buf_get(fd) // Get the dmabuf from fd b) dma_buf_attach(dmabuf); // Clients attach to the dmabuf o Here the kernel does some slab allocations, say for dma_buf_attachment and may be some other slab allocation in the dmabuf->ops->attach(). c) Client may need to do dma_buf_map_attachment(). d) Accordingly dma_buf_unmap_attachment() should be called. e) dma_buf_detach () // Clients detach to the dmabuf. o Here the slab allocations made in b) are freed. f) dma_buf_put(dmabuf) // Can free the dmabuf if it is the last reference. Now say an erroneous client failed at step c) above thus it directly called dma_buf_put(), step f) above. Considering that it may be the last reference to the dmabuf, buffer will be freed with pending attachments left to the dmabuf which can show up as the 'memory leak'. This should at least be reported as the WARN(). Signed-off-by:
Charan Teja Reddy <charante@codeaurora.org> Reviewed-by:
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Christian König authored
Entirely unused. Signed-off-by:
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- Aug 12, 2021
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Syzbot reported general protection fault in udmabuf_create. The problem was in wrong error handling. In commit 16c243e9 ("udmabuf: Add support for mapping hugepages (v4)") shmem_read_mapping_page() call was replaced with find_get_page_flags(), but find_get_page_flags() returns NULL on failure instead PTR_ERR(). Wrong error checking was causing GPF in get_page(), since passed page was equal to NULL. Fix it by changing if (IS_ER(!hpage)) to if (!hpage) Reported-by:
<syzbot+e9cd3122a37c5d6c51e8@syzkaller.appspotmail.com> Fixes: 16c243e9 ("udmabuf: Add support for mapping hugepages (v4)") Signed-off-by:
Pavel Skripkin <paskripkin@gmail.com> Link: http://patchwork.freedesktop.org/patch/msgid/20210811175052.21254-1-paskripkin@gmail.com Signed-off-by:
Gerd Hoffmann <kraxel@redhat.com>
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- Jul 20, 2021
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Dmabuf sysfs stat is used for dmabuf info track. But these file maybe still in use after buffer released, should clear it before buffer release. Signed-off-by:
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The DMA-BUF attachment statistics form a subset of the DMA-BUF sysfs statistics that recently merged to the drm-misc tree. They are not UABI yet since they have not merged to the upstream Linux kernel. Since there has been a reported a performance regression due to the overhead of sysfs directory creation/teardown during dma_buf_attach()/dma_buf_detach(), this patch deletes the DMA-BUF attachment statistics from sysfs. Fixes: bdb8d06d ("dmabuf: Add the capability to expose DMA-BUF stats in sysfs") Signed-off-by:
Hridya Valsaraju <hridya@google.com> Reviewed-by:
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- Jul 12, 2021
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Each add_fence() call does a dma_fence_get() on the relevant fence. In the error path, we weren't calling dma_fence_put() so all those fences got leaked. Also, in the krealloc_array failure case, we weren't freeing the fences array. Instead, ensure that i and fences are always zero-initialized and dma_fence_put() all the fences and kfree(fences) on every error path. Signed-off-by:
Jason Ekstrand <jason@jlekstrand.net> Reviewed-by:
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- Jul 08, 2021
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Christian König authored
As the name implies if testing all fences is requested we should indeed test all fences and not skip the exclusive one because we see shared ones. v2: fix logic once more Signed-off-by:
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- Jun 23, 2021
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Default list_limit and size_limit_mb are not big enough to cover all possible use cases. For example, list_limit could be well over its default, 1024 if only one or several pages are chained in all individual list entries when creating dmabuf backed by >4MB buffer. list_limit and size_limit_mb are now defined as module parameters so that those can be optionally configured by root with proper values to remove these constraints. Cc: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by:
Dongwon Kim <dongwon.kim@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20210611212107.9876-1-dongwon.kim@intel.com Signed-off-by:
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- Jun 22, 2021
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Simona Vetter authored
Christian and me realized we have a pretty massive disconnect about different interpretations of what dma_resv is used for by different drivers. The discussion is much, much bigger than this change here, but this is an important one: Non-dynamic exporters must guarantee that the memory they return is ready for use. They cannot expect importers to wait for the exclusive fence. Only dynamic importers are required to obey the dma_resv fences strictly (and more patches are needed to define exactly what this means). Christian has patches to update nouvea, radeon and amdgpu. The only other driver using both ttm and supporting dma-buf export is qxl, which only uses synchronous ttm_bo_move. v2: To hammer this in document that dynamic importers _must_ wait for the exclusive fence after having called dma_buf_map_attachment. Reviewed-by:
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- Jun 15, 2021
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Overview ======== The patch adds DMA-BUF statistics to /sys/kernel/dmabuf/buffers. It allows statistics to be enabled for each DMA-BUF in sysfs by enabling the config CONFIG_DMABUF_SYSFS_STATS. The following stats will be exposed by the interface: /sys/kernel/dmabuf/buffers/<inode_number>/exporter_name /sys/kernel/dmabuf/buffers/<inode_number>/size /sys/kernel/dmabuf/buffers/<inode_number>/attachments/<attach_uid>/device /sys/kernel/dmabuf/buffers/<inode_number>/attachments/<attach_uid>/map_counter The inode_number is unique for each DMA-BUF and was added earlier [1] in order to allow userspace to track DMA-BUF usage across different processes. Use Cases ========= The interface provides a way to gather DMA-BUF per-buffer statistics from production devices. These statistics will be used to derive DMA-BUF per-exporter stats and per-device usage stats for Android Bug reports. The corresponding userspace changes can be found at [2]. Telemetry tools will also capture this information(along with other memory metrics) periodically as well as on important events like a foreground app kill (which might have been triggered by Low Memory Killer). It will also contribute to provide a snapshot of the system memory usage on other events such as OOM kills and Application Not Responding events. Background ========== Currently, there are two existing interfaces that provide information about DMA-BUFs. 1) /sys/kernel/debug/dma_buf/bufinfo debugfs is however unsuitable to be mounted in production systems and cannot be considered as an alternative to the sysfs interface being proposed. 2) proc/<pid>/fdinfo/<fd> The proc/<pid>/fdinfo/<fd> files expose information about DMA-BUF fds. However, the existing procfs interfaces can only provide information about the buffers for which processes hold fds or have the buffers mmapped into their address space. Since the procfs interfaces alone cannot provide a full picture of all DMA-BUFs in the system, there is the need for an alternate interface to provide this information on production systems. The patch contains the following major improvements over v1: 1) Each attachment is represented by its own directory to allow creating a symlink to the importing device and to also provide room for future expansion. 2) The number of distinct mappings of each attachment is exposed in a separate file. 3) The per-buffer statistics are now in /sys/kernel/dmabuf/buffers inorder to make the interface expandable in future. All of the improvements above are based on suggestions/feedback from Daniel Vetter and Christian König. A shell script that can be run on a classic Linux environment to read out the DMA-BUF statistics can be found at [3](suggested by John Stultz). [1]: https://lore.kernel.org/patchwork/patch/1088791/ [2]: https://android-review.googlesource.com/q/topic:%22dmabuf-sysfs%22+(status:open%20OR%20status:merged) [3]: https://android-review.googlesource.com/c/platform/system/memory/libmeminfo/+/1549734 Reviewed-by:
kernel test robot <lkp@intel.com> Signed-off-by:
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- Jun 14, 2021
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Christian König authored
Add a common allocation helper. Cleaning up the mix of kzalloc/kmalloc and some unused code in the selftest. v2: polish kernel doc a bit v3: polish kernel doc even a bit more Signed-off-by:
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Christian König authored
The callback and the irq work are never used at the same time. Putting them into an union saves us 24 bytes and makes the structure only 120 bytes in size. Signed-off-by:
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