kernel/include/trace/events, branch linux-6.12.y

tracing/dma: Cap dma_map_sg tracepoint arrays to prevent buffer overflow

2026-02-19T15:29:54Z

[ Upstream commit daafcc0ef0b358d9d622b6e3b7c43767aa3814ee ] The dma_map_sg tracepoint can trigger a perf buffer overflow when tracing large scatter-gather lists. With devices like virtio-gpu creating large DRM buffers, nents can exceed 1000 entries, resulting in: phys_addrs: 1000 * 8 bytes = 8,000 bytes dma_addrs: 1000 * 8 bytes = 8,000 bytes lengths: 1000 * 4 bytes = 4,000 bytes Total: ~20,000 bytes This exceeds PERF_MAX_TRACE_SIZE (8192 bytes), causing: WARNING: CPU: 0 PID: 5497 at kernel/trace/trace_event_perf.c:405 perf buffer not large enough, wanted 24620, have 8192 Cap all three dynamic arrays at 128 entries using min() in the array size calculation. This ensures arrays are only as large as needed (up to the cap), avoiding unnecessary memory allocation for small operations while preventing overflow for large ones. The tracepoint now records the full nents/ents counts and a truncated flag so users can see when data has been capped. Changes in v2: - Use min(nents, DMA_TRACE_MAX_ENTRIES) for dynamic array sizing instead of fixed DMA_TRACE_MAX_ENTRIES allocation (feedback from Steven Rostedt) - This allocates only what's needed up to the cap, avoiding waste for small operations Reported-by: syzbot+28cea38c382fd15e751a@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=28cea38c382fd15e751a Tested-by: syzbot+28cea38c382fd15e751a@syzkaller.appspotmail.com Signed-off-by: Deepanshu Kartikey Reviwed-by: Sean Anderson Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/20260130155215.69737-1-kartikey406@gmail.com Signed-off-by: Sasha Levin

btrfs: fix NULL dereference on root when tracing inode eviction

2026-01-17T15:31:20Z

[ Upstream commit f157dd661339fc6f5f2b574fe2429c43bd309534 ] When evicting an inode the first thing we do is to setup tracing for it, which implies fetching the root's id. But in btrfs_evict_inode() the root might be NULL, as implied in the next check that we do in btrfs_evict_inode(). Hence, we either should set the ->root_objectid to 0 in case the root is NULL, or we move tracing setup after checking that the root is not NULL. Setting the rootid to 0 at least gives us the possibility to trace this call even in the case when the root is NULL, so that's the solution taken here. Fixes: 1abe9b8a138c ("Btrfs: add initial tracepoint support for btrfs") Reported-by: syzbot+d991fea1b4b23b1f6bf8@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d991fea1b4b23b1f6bf8 Signed-off-by: Miquel Sabaté Solà Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: tracepoints: use btrfs_root_id() to get the id of a root

2026-01-17T15:31:20Z

[ Upstream commit 0f987c099d22c3b8c7d94fd13f957792e46f79c9 ] Instead of open coding btrfs_root_id() to get the ID of a root, use the helper in the trace points, which also makes the code less verbose. Reviewed-by: Qu Wenruo Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Stable-dep-of: f157dd661339 ("btrfs: fix NULL dereference on root when tracing inode eviction") Signed-off-by: Sasha Levin

dma-mapping: fix direction in dma_alloc direction traces

2025-10-19T14:33:34Z

commit 16abbabc004bedeeaa702e11913da9d4fa70e63a upstream. Set __entry->dir to the actual "dir" parameter of all trace events in dma_alloc_class. This struct member was left uninitialized by mistake. Signed-off-by: Petr Tesarik Fixes: 3afff779a725 ("dma-mapping: trace dma_alloc/free direction") Cc: stable@vger.kernel.org Reviewed-by: Sean Anderson Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/20251001061028.412258-1-ptesarik@suse.com Signed-off-by: Greg Kroah-Hartman

filelock: add FL_RECLAIM to show_fl_flags() macro

2025-10-15T09:59:53Z

[ Upstream commit c593b9d6c446510684da400833f9d632651942f0 ] Show the FL_RECLAIM flag symbolically in tracepoints. Fixes: bb0a55bb7148 ("nfs: don't allow reexport reclaims") Signed-off-by: Jeff Layton Link: https://lore.kernel.org/20250903-filelock-v1-1-f2926902962d@kernel.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

dma-mapping: trace more error paths

2025-09-19T14:35:42Z

[ Upstream commit 68b6dbf1f441c4eba3b8511728a41cf9b01dca35 ] It can be surprising to the user if DMA functions are only traced on success. On failure, it can be unclear what the source of the problem is. Fix this by tracing all functions even when they fail. Cases where we BUG/WARN are skipped, since those should be sufficiently noisy already. Signed-off-by: Sean Anderson Reviewed-by: Steven Rostedt (Google) Signed-off-by: Christoph Hellwig Stable-dep-of: 7e2368a21741 ("dma-debug: don't enforce dma mapping check on noncoherent allocations") Signed-off-by: Sasha Levin

dma-mapping: use trace_dma_alloc for dma_alloc* instead of using trace_dma_map

2025-09-19T14:35:42Z

[ Upstream commit c4484ab86ee00f2d9236e2851621ea02c105f4cc ] In some cases, we use trace_dma_map to trace dma_alloc* functions. This generally follows dma_debug. However, this does not record all of the relevant information for allocations, such as GFP flags. Create new dma_alloc tracepoints for these functions. Note that while dma_alloc_noncontiguous may allocate discontiguous pages (from the CPU's point of view), the device will only see one contiguous mapping. Therefore, we just need to trace dma_addr and size. Signed-off-by: Sean Anderson Reviewed-by: Steven Rostedt (Google) Signed-off-by: Christoph Hellwig Stable-dep-of: 7e2368a21741 ("dma-debug: don't enforce dma mapping check on noncoherent allocations") Signed-off-by: Sasha Levin

dma-mapping: trace dma_alloc/free direction

2025-09-19T14:35:41Z

[ Upstream commit 3afff779a725cba914e6caba360b696ae6f90249 ] In preparation for using these tracepoints in a few more places, trace the DMA direction as well. For coherent allocations this is always bidirectional. Signed-off-by: Sean Anderson Reviewed-by: Steven Rostedt (Google) Signed-off-by: Christoph Hellwig Stable-dep-of: 7e2368a21741 ("dma-debug: don't enforce dma mapping check on noncoherent allocations") Signed-off-by: Sasha Levin

powerpc/thp: tracing: Hide hugepage events under CONFIG_PPC_BOOK3S_64

2025-08-20T16:30:28Z

[ Upstream commit 43cf0e05089afe23dac74fa6e1e109d49f2903c4 ] The events hugepage_set_pmd, hugepage_set_pud, hugepage_update_pmd and hugepage_update_pud are only called when CONFIG_PPC_BOOK3S_64 is defined. As each event can take up to 5K regardless if they are used or not, it's best not to define them when they are not used. Add #ifdef around these events when they are not used. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Michael Ellerman Link: https://lore.kernel.org/20250612101259.0ad43e48@batman.local.home Acked-by: David Hildenbrand Acked-by: Madhavan Srinivasan Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin

rxrpc: Fix recv-recv race of completed call

2025-07-24T06:56:35Z

[ Upstream commit 962fb1f651c2cf2083e0c3ef53ba69e3b96d3fbc ] If a call receives an event (such as incoming data), the call gets placed on the socket's queue and a thread in recvmsg can be awakened to go and process it. Once the thread has picked up the call off of the queue, further events will cause it to be requeued, and once the socket lock is dropped (recvmsg uses call->user_mutex to allow the socket to be used in parallel), a second thread can come in and its recvmsg can pop the call off the socket queue again. In such a case, the first thread will be receiving stuff from the call and the second thread will be blocked on call->user_mutex. The first thread can, at this point, process both the event that it picked call for and the event that the second thread picked the call for and may see the call terminate - in which case the call will be "released", decoupling the call from the user call ID assigned to it (RXRPC_USER_CALL_ID in the control message). The first thread will return okay, but then the second thread will wake up holding the user_mutex and, if it sees that the call has been released by the first thread, it will BUG thusly: kernel BUG at net/rxrpc/recvmsg.c:474! Fix this by just dequeuing the call and ignoring it if it is seen to be already released. We can't tell userspace about it anyway as the user call ID has become stale. Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code") Reported-by: Junvyyang, Tencent Zhuque Lab Signed-off-by: David Howells Reviewed-by: Jeffrey Altman cc: LePremierHomme cc: Marc Dionne cc: Simon Horman cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20250717074350.3767366-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin