linux/drivers/dma-buf, branch v5.9

dmabuf: fix NULL pointer dereference in dma_buf_release()

2020-09-21T09:17:06Z

NULL pointer dereference is observed while exporting the dmabuf but failed to allocate the 'struct file' which results into the dropping of the allocated dentry corresponding to this file in the dmabuf fs, which is ending up in dma_buf_release() and accessing the uninitialzed dentry->d_fsdata. Call stack on 5.4 is below: dma_buf_release+0x2c/0x254 drivers/dma-buf/dma-buf.c:88 __dentry_kill+0x294/0x31c fs/dcache.c:584 dentry_kill fs/dcache.c:673 [inline] dput+0x250/0x380 fs/dcache.c:859 path_put+0x24/0x40 fs/namei.c:485 alloc_file_pseudo+0x1a4/0x200 fs/file_table.c:235 dma_buf_getfile drivers/dma-buf/dma-buf.c:473 [inline] dma_buf_export+0x25c/0x3ec drivers/dma-buf/dma-buf.c:585 Fix this by checking for the valid pointer in the dentry->d_fsdata. Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops") Cc: [5.7+] Signed-off-by: Charan Teja Reddy Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/391319/ Signed-off-by: Christian König

dma-buf: fence-chain: Document missing dma_fence_chain_init() parameter in kerneldoc

2020-09-03T12:17:02Z

Fix W=1 compile warnings (invalid kerneldoc): drivers/dma-buf/dma-fence-chain.c:233: warning: Function parameter or member 'seqno' not described in 'dma_fence_chain_init' Signed-off-by: Krzysztof Kozlowski Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20200819175134.19261-2-krzk@kernel.org

dma-buf: Fix kerneldoc of dma_buf_set_name()

2020-09-03T12:16:46Z

Fix W=1 compile warnings (invalid kerneldoc): drivers/dma-buf/dma-buf.c:328: warning: Function parameter or member 'dmabuf' not described in 'dma_buf_set_name' Signed-off-by: Krzysztof Kozlowski Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20200819175134.19261-1-krzk@kernel.org

Merge tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-08-11T02:07:44Z

Pull locking updates from Thomas Gleixner: "A set of locking fixes and updates: - Untangle the header spaghetti which causes build failures in various situations caused by the lockdep additions to seqcount to validate that the write side critical sections are non-preemptible. - The seqcount associated lock debug addons which were blocked by the above fallout. seqcount writers contrary to seqlock writers must be externally serialized, which usually happens via locking - except for strict per CPU seqcounts. As the lock is not part of the seqcount, lockdep cannot validate that the lock is held. This new debug mechanism adds the concept of associated locks. sequence count has now lock type variants and corresponding initializers which take a pointer to the associated lock used for writer serialization. If lockdep is enabled the pointer is stored and write_seqcount_begin() has a lockdep assertion to validate that the lock is held. Aside of the type and the initializer no other code changes are required at the seqcount usage sites. The rest of the seqcount API is unchanged and determines the type at compile time with the help of _Generic which is possible now that the minimal GCC version has been moved up. Adding this lockdep coverage unearthed a handful of seqcount bugs which have been addressed already independent of this. While generally useful this comes with a Trojan Horse twist: On RT kernels the write side critical section can become preemtible if the writers are serialized by an associated lock, which leads to the well known reader preempts writer livelock. RT prevents this by storing the associated lock pointer independent of lockdep in the seqcount and changing the reader side to block on the lock when a reader detects that a writer is in the write side critical section. - Conversion of seqcount usage sites to associated types and initializers" * tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits) locking/seqlock, headers: Untangle the spaghetti monster locking, arch/ia64: Reduce header dependencies by moving XTP bits into the new header x86/headers: Remove APIC headers from seqcount: More consistent seqprop names seqcount: Compress SEQCNT_LOCKNAME_ZERO() seqlock: Fold seqcount_LOCKNAME_init() definition seqlock: Fold seqcount_LOCKNAME_t definition seqlock: s/__SEQ_LOCKDEP/__SEQ_LOCK/g hrtimer: Use sequence counter with associated raw spinlock kvm/eventfd: Use sequence counter with associated spinlock userfaultfd: Use sequence counter with associated spinlock NFSv4: Use sequence counter with associated spinlock iocost: Use sequence counter with associated spinlock raid5: Use sequence counter with associated spinlock vfs: Use sequence counter with associated spinlock timekeeping: Use sequence counter with associated raw spinlock xfrm: policy: Use sequence counters with associated lock netfilter: nft_set_rbtree: Use sequence counter with associated rwlock netfilter: conntrack: Use sequence counter with associated spinlock sched: tasks: Use sequence counter with associated spinlock ...

dma-buf: Use sequence counter with associated wound/wait mutex

2020-07-29T14:14:25Z

A sequence counter write side critical section must be protected by some form of locking to serialize writers. If the serialization primitive is not disabling preemption implicitly, preemption has to be explicitly disabled before entering the sequence counter write side critical section. The dma-buf reservation subsystem uses plain sequence counters to manage updates to reservations. Writer serialization is accomplished through a wound/wait mutex. Acquiring a wound/wait mutex does not disable preemption, so this needs to be done manually before and after the write side critical section. Use the newly-added seqcount_ww_mutex_t instead: - It associates the ww_mutex with the sequence count, which enables lockdep to validate that the write side critical section is properly serialized. - It removes the need to explicitly add preempt_disable/enable() around the write side critical section because the write_begin/end() functions for this new data type automatically do this. If lockdep is disabled this ww_mutex lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish Signed-off-by: Peter Zijlstra (Intel) Acked-by: Daniel Vetter Link: https://lkml.kernel.org/r/20200720155530.1173732-13-a.darwish@linutronix.de

dma-buf: Remove custom seqcount lockdep class key

2020-07-29T14:14:25Z

Commit 3c3b177a9369 ("reservation: add support for read-only access using rcu") introduced a sequence counter to manage updates to reservations. Back then, the reservation object initializer reservation_object_init() was always inlined. Having the sequence counter initialization inlined meant that each of the call sites would have a different lockdep class key, which would've broken lockdep's deadlock detection. The aforementioned commit thus introduced, and exported, a custom seqcount lockdep class key and name. The commit 8735f16803f00 ("dma-buf: cleanup reservation_object_init...") transformed the reservation object initializer to a normal non-inlined C function. seqcount_init(), which automatically defines the seqcount lockdep class key and must be called non-inlined, can now be safely used. Remove the seqcount custom lockdep class key, name, and export. Use seqcount_init() inside the dma reservation object initializer. Signed-off-by: Ahmed S. Darwish Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Sebastian Andrzej Siewior Acked-by: Daniel Vetter Link: https://lkml.kernel.org/r/20200720155530.1173732-12-a.darwish@linutronix.de

Merge v5.8-rc6 into drm-next

2020-07-23T22:48:05Z

I've got a silent conflict + two trees based on fixes to merge. Fixes a silent merge with amdgpu Signed-off-by: Dave Airlie

dma-fence: Make symbol 'dma_fence_lockdep_map' static

2020-07-23T04:33:12Z

The sparse tool complains as follows: drivers/dma-buf/dma-fence.c:249:25: warning: symbol 'dma_fence_lockdep_map' was not declared. Should it be static? This variable is not used outside of dma-fence.c, so this commit marks it static. Fixes: 5fbff813a4a3 ("dma-fence: basic lockdep annotations") Reported-by: Hulk Robot Signed-off-by: Wei Yongjun Reviewed-by: Christian König Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/dc5e3b19-2087-44ab-a28c-ddb38ff8861a@email.android.com

Merge tag 'drm-misc-next-2020-07-22' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

2020-07-23T04:01:45Z

drm-misc-next for v5.9: UAPI Changes: Cross-subsystem Changes: - Convert panel-dsi-cm and ingenic bindings to YAML. - Add lockdep annotations for dma-fence. \o/ - Describe why indefinite fences are a bad idea - Update binding for rocktech jh057n00900. Core Changes: - Add vblank workers. - Use spin_(un)lock_irq instead of the irqsave/restore variants in crtc code. - Add managed vram helpers. - Convert more logging to drm functions. - Replace more http links with https in core and drivers. - Cleanup to ttm iomem functions and implementation. - Remove TTM CMA memtype as it doesn't work correctly. - Remove TTM_MEMTYPE_FLAG_MAPPABLE for many drivers that have no unmappable memory resources. Driver Changes: - Add CRC support to nouveau, using the new vblank workers. - Dithering and atomic state fix for nouveau. - Fixes for Frida FRD350H54004 panel. - Add support for OSD mode (sprite planes), IPU (scaling) and multiple panels/bridges to ingenic. - Use managed vram helpers in ast. - Assorted small fixes to ingenic, i810, mxsfb. - Remove optional unused ttm dummy functions. Signed-off-by: Dave Airlie From: Maarten Lankhorst Link: https://patchwork.freedesktop.org/patch/msgid/d6bf269e-ccb2-8a7b-fdae-226e9e3f8274@linux.intel.com

dma-fence: prime lockdep annotations

2020-07-21T07:42:19Z

Two in one go: - it is allowed to call dma_fence_wait() while holding a dma_resv_lock(). This is fundamental to how eviction works with ttm, so required. - it is allowed to call dma_fence_wait() from memory reclaim contexts, specifically from shrinker callbacks (which i915 does), and from mmu notifier callbacks (which amdgpu does, and which i915 sometimes also does, and probably always should, but that's kinda a debate). Also for stuff like HMM we really need to be able to do this, or things get real dicey. Consequence is that any critical path necessary to get to a dma_fence_signal for a fence must never a) call dma_resv_lock nor b) allocate memory with GFP_KERNEL. Also by implication of dma_resv_lock(), no userspace faulting allowed. That's some supremely obnoxious limitations, which is why we need to sprinkle the right annotations to all relevant paths. The one big locking context we're leaving out here is mmu notifiers, added in commit 23b68395c7c78a764e8963fc15a7cfd318bf187f Author: Daniel Vetter Date: Mon Aug 26 22:14:21 2019 +0200 mm/mmu_notifiers: add a lockdep map for invalidate_range_start/end that one covers a lot of other callsites, and it's also allowed to wait on dma-fences from mmu notifiers. But there's no ready-made functions exposed to prime this, so I've left it out for now. v2: Also track against mmu notifier context. v3: kerneldoc to spec the cross-driver contract. Note that currently i915 throws in a hard-coded 10s timeout on foreign fences (not sure why that was done, but it's there), which is why that rule is worded with SHOULD instead of MUST. Also some of the mmu_notifier/shrinker rules might surprise SoC drivers, I haven't fully audited them all. Which is infeasible anyway, we'll need to run them with lockdep and dma-fence annotations and see what goes boom. v4: A spelling fix from Mika v5: #ifdef for CONFIG_MMU_NOTIFIER. Reported by 0day. Unfortunately this means lockdep enforcement is slightly inconsistent, it won't spot GFP_NOIO and GFP_NOFS allocations in the wrong spot if CONFIG_MMU_NOTIFIER is disabled in the kernel config. Oh well. v5: Note that only drivers/gpu has a reasonable (or at least historical) excuse to use dma_fence_wait() from shrinker and mmu notifier callbacks. Everyone else should either have a better memory manager model, or better hardware. This reflects discussions with Jason Gunthorpe. Cc: Jason Gunthorpe Cc: Felix Kuehling Cc: kernel test robot Acked-by: Christian König Acked-by: Dave Airlie Reviewed-by: Maarten Lankhorst Reviewed-by: Thomas Hellström (v4) Cc: Mika Kuoppala Cc: Thomas Hellstrom Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Cc: linux-rdma@vger.kernel.org Cc: amd-gfx@lists.freedesktop.org Cc: intel-gfx@lists.freedesktop.org Cc: Chris Wilson Cc: Maarten Lankhorst Cc: Christian König Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200707201229.472834-3-daniel.vetter@ffwll.ch