Linaro-mm-sig March 2026

linaro-mm-sig@lists.linaro.org

92 participants
58 discussions

[PATCH 00/15] tracepoint: Avoid double static_branch evaluation at guarded call sites

by Vineeth Pillai (Google)

When a caller already guards a tracepoint with an explicit enabled check: if (trace_foo_enabled() && cond) trace_foo(args); trace_foo() internally re-evaluates the static_branch_unlikely() key. Since static branches are patched binary instructions the compiler cannot fold the two evaluations, so every such site pays the cost twice. This series introduces trace_invoke_##name() as a companion to trace_##name(). It calls __do_trace_##name() directly, bypassing the redundant static-branch re-check, while preserving all other correctness properties of the normal path (RCU-watching assertion, might_fault() for syscall tracepoints). The internal __do_trace_##name() symbol is not leaked to call sites; trace_invoke_##name() is the only new public API. if (trace_foo_enabled() && cond) trace_invoke_foo(args); /* calls __do_trace_foo() directly */ The first patch adds the three-location change to include/linux/tracepoint.h (__DECLARE_TRACE, __DECLARE_TRACE_SYSCALL, and the !TRACEPOINTS_ENABLED stub). The remaining 14 patches mechanically convert all guarded call sites found in the tree: kernel/, io_uring/, net/, accel/habanalabs, cpufreq/, devfreq/, dma-buf/, fsi/, drm/, HID, i2c/, spi/, scsi/ufs/, and btrfs/. This series is motivated by Peter Zijlstra's observation in the discussion around Dmitry Ilvokhin's locking tracepoint instrumentation series, where he noted that compilers cannot optimize static branches and that guarded call sites end up evaluating the static branch twice for no reason, and by Steven Rostedt's suggestion to add a proper API instead of exposing internal implementation details like __do_trace_##name() directly to call sites: https://lore.kernel.org/linux-trace-kernel/8298e098d3418cb446ef396f119edac5… Suggested-by: Steven Rostedt <rostedt(a)goodmis.org> Suggested-by: Peter Zijlstra <peterz(a)infradead.org> Vineeth Pillai (Google) (15): tracepoint: Add trace_invoke_##name() API kernel: Use trace_invoke_##name() at guarded tracepoint call sites io_uring: Use trace_invoke_##name() at guarded tracepoint call sites net: Use trace_invoke_##name() at guarded tracepoint call sites accel/habanalabs: Use trace_invoke_##name() at guarded tracepoint call sites cpufreq: Use trace_invoke_##name() at guarded tracepoint call sites devfreq: Use trace_invoke_##name() at guarded tracepoint call sites dma-buf: Use trace_invoke_##name() at guarded tracepoint call sites fsi: Use trace_invoke_##name() at guarded tracepoint call sites drm: Use trace_invoke_##name() at guarded tracepoint call sites HID: Use trace_invoke_##name() at guarded tracepoint call sites i2c: Use trace_invoke_##name() at guarded tracepoint call sites spi: Use trace_invoke_##name() at guarded tracepoint call sites scsi: ufs: Use trace_invoke_##name() at guarded tracepoint call sites btrfs: Use trace_invoke_##name() at guarded tracepoint call sites drivers/accel/habanalabs/common/device.c | 12 ++++++------ drivers/accel/habanalabs/common/mmu/mmu.c | 3 ++- drivers/accel/habanalabs/common/pci/pci.c | 4 ++-- drivers/cpufreq/amd-pstate.c | 10 +++++----- drivers/cpufreq/cpufreq.c | 2 +- drivers/cpufreq/intel_pstate.c | 2 +- drivers/devfreq/devfreq.c | 2 +- drivers/dma-buf/dma-fence.c | 4 ++-- drivers/fsi/fsi-master-aspeed.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 ++-- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +- drivers/gpu/drm/scheduler/sched_entity.c | 4 ++-- drivers/hid/intel-ish-hid/ipc/pci-ish.c | 2 +- drivers/i2c/i2c-core-slave.c | 2 +- drivers/spi/spi-axi-spi-engine.c | 4 ++-- drivers/ufs/core/ufshcd.c | 12 ++++++------ fs/btrfs/extent_map.c | 4 ++-- fs/btrfs/raid56.c | 4 ++-- include/linux/tracepoint.h | 11 +++++++++++ io_uring/io_uring.h | 2 +- kernel/irq_work.c | 2 +- kernel/sched/ext.c | 2 +- kernel/smp.c | 2 +- net/core/dev.c | 2 +- net/core/xdp.c | 2 +- net/openvswitch/actions.c | 2 +- net/openvswitch/datapath.c | 2 +- net/sctp/outqueue.c | 2 +- net/tipc/node.c | 2 +- 30 files changed, 62 insertions(+), 50 deletions(-) -- 2.53.0

7 months, 2 weeks

[PATCH] udmabuf: Do not create malformed scatterlists

by Jason Gunthorpe

Using a sg_set_folio() loop for every 4K results in a malformed scatterlist because sg_set_folio() has an issue with offsets > PAGE_SIZE and because scatterlist expects the creator to build a list which consolidates any physical contiguity. sg_alloc_table_from_pages() creates a valid scatterlist directly from a struct page array, so go back to that. Remove the offsets allocation and just store an array of tail pages as it did before the below commit. Everything wants that anyhow. Fixes: 0c8b91ef5100 ("udmabuf: add back support for mapping hugetlb pages") Reported-by: Julian Orth <ju.orth(a)gmail.com> Closes: https://lore.kernel.org/all/20260308-scatterlist-v1-1-39c4566b0bba@gmail.co… Signed-off-by: Jason Gunthorpe <jgg(a)nvidia.com> --- drivers/dma-buf/udmabuf.c | 49 +++++++++++---------------------------- 1 file changed, 13 insertions(+), 36 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 94b8ecb892bb17..5d687860445137 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -26,10 +26,10 @@ MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is struct udmabuf { pgoff_t pagecount; - struct folio **folios; + struct page **pages; /** - * Unlike folios, pinned_folios is only used for unpin. + * Unlike pages, pinned_folios is only used for unpin. * So, nr_pinned is not the same to pagecount, the pinned_folios * only set each folio which already pinned when udmabuf_create. * Note that, since a folio may be pinned multiple times, each folio @@ -41,7 +41,6 @@ struct udmabuf { struct sg_table *sg; struct miscdevice *device; - pgoff_t *offsets; }; static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) @@ -55,8 +54,7 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) if (pgoff >= ubuf->pagecount) return VM_FAULT_SIGBUS; - pfn = folio_pfn(ubuf->folios[pgoff]); - pfn += ubuf->offsets[pgoff] >> PAGE_SHIFT; + pfn = page_to_pfn(ubuf->pages[pgoff]); ret = vmf_insert_pfn(vma, vmf->address, pfn); if (ret & VM_FAULT_ERROR) @@ -73,8 +71,7 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) if (WARN_ON(pgoff >= ubuf->pagecount)) break; - pfn = folio_pfn(ubuf->folios[pgoff]); - pfn += ubuf->offsets[pgoff] >> PAGE_SHIFT; + pfn = page_to_pfn(ubuf->pages[pgoff]); /** * If the below vmf_insert_pfn() fails, we do not return an @@ -109,22 +106,11 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma) static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map) { struct udmabuf *ubuf = buf->priv; - struct page **pages; void *vaddr; - pgoff_t pg; dma_resv_assert_held(buf->resv); - pages = kvmalloc_objs(*pages, ubuf->pagecount); - if (!pages) - return -ENOMEM; - - for (pg = 0; pg < ubuf->pagecount; pg++) - pages[pg] = folio_page(ubuf->folios[pg], - ubuf->offsets[pg] >> PAGE_SHIFT); - - vaddr = vm_map_ram(pages, ubuf->pagecount, -1); - kvfree(pages); + vaddr = vm_map_ram(ubuf->pages, ubuf->pagecount, -1); if (!vaddr) return -EINVAL; @@ -146,22 +132,18 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, { struct udmabuf *ubuf = buf->priv; struct sg_table *sg; - struct scatterlist *sgl; - unsigned int i = 0; int ret; sg = kzalloc_obj(*sg); if (!sg) return ERR_PTR(-ENOMEM); - ret = sg_alloc_table(sg, ubuf->pagecount, GFP_KERNEL); + ret = sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->pagecount, 0, + ubuf->pagecount << PAGE_SHIFT, + GFP_KERNEL); if (ret < 0) goto err_alloc; - for_each_sg(sg->sgl, sgl, ubuf->pagecount, i) - sg_set_folio(sgl, ubuf->folios[i], PAGE_SIZE, - ubuf->offsets[i]); - ret = dma_map_sgtable(dev, sg, direction, 0); if (ret < 0) goto err_map; @@ -207,12 +189,8 @@ static void unpin_all_folios(struct udmabuf *ubuf) static __always_inline int init_udmabuf(struct udmabuf *ubuf, pgoff_t pgcnt) { - ubuf->folios = kvmalloc_objs(*ubuf->folios, pgcnt); - if (!ubuf->folios) - return -ENOMEM; - - ubuf->offsets = kvzalloc_objs(*ubuf->offsets, pgcnt); - if (!ubuf->offsets) + ubuf->pages = kvmalloc_objs(*ubuf->pages, pgcnt); + if (!ubuf->pages) return -ENOMEM; ubuf->pinned_folios = kvmalloc_objs(*ubuf->pinned_folios, pgcnt); @@ -225,8 +203,7 @@ static __always_inline int init_udmabuf(struct udmabuf *ubuf, pgoff_t pgcnt) static __always_inline void deinit_udmabuf(struct udmabuf *ubuf) { unpin_all_folios(ubuf); - kvfree(ubuf->offsets); - kvfree(ubuf->folios); + kvfree(ubuf->pages); } static void release_udmabuf(struct dma_buf *buf) @@ -344,8 +321,8 @@ static long udmabuf_pin_folios(struct udmabuf *ubuf, struct file *memfd, ubuf->pinned_folios[nr_pinned++] = folios[cur_folio]; for (; subpgoff < fsize; subpgoff += PAGE_SIZE) { - ubuf->folios[upgcnt] = folios[cur_folio]; - ubuf->offsets[upgcnt] = subpgoff; + ubuf->pages[upgcnt] = folio_page(folios[cur_folio], + subpgoff >> PAGE_SHIFT); ++upgcnt; if (++cur_pgcnt >= pgcnt) base-commit: 1f318b96cc84d7c2ab792fcc0bfd42a7ca890681 -- 2.43.0

7 months, 2 weeks

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7 months, 2 weeks

5
4
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[PATCH v8 0/7] Rust bindings for gem shmem + iosys_map

by Lyude Paul

This is the next version of the shmem backed GEM objects series originally from Asahi, previously posted by Daniel Almeida. One of the major changes in this patch series is a much better interface around vmaps, which we achieve by introducing a new set of rust bindings for iosys_map. The previous version of the patch series can be found here: https://patchwork.freedesktop.org/series/156093/ This patch series may be applied on top of the driver-core/driver-core-testing branch: https://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core.git… Changelogs are per-patch Asahi Lina (2): rust: helpers: Add bindings/wrappers for dma_resv_lock rust: drm: gem: shmem: Add DRM shmem helper abstraction Lyude Paul (5): rust: drm: Add gem::impl_aref_for_gem_obj! rust: drm: gem: Add raw_dma_resv() function rust: gem: Introduce DriverObject::Args rust: drm: gem: Introduce shmem::SGTable rust: drm/gem: Add vmap functions to shmem bindings drivers/gpu/drm/nova/gem.rs | 5 +- drivers/gpu/drm/tyr/gem.rs | 3 +- rust/bindings/bindings_helper.h | 3 + rust/helpers/dma-resv.c | 13 + rust/helpers/drm.c | 56 +++- rust/helpers/helpers.c | 1 + rust/kernel/drm/gem/mod.rs | 79 +++-- rust/kernel/drm/gem/shmem.rs | 529 ++++++++++++++++++++++++++++++++ 8 files changed, 667 insertions(+), 22 deletions(-) create mode 100644 rust/helpers/dma-resv.c create mode 100644 rust/kernel/drm/gem/shmem.rs -- 2.53.0

7 months, 2 weeks

Re: [PATCH] lib/scatterlist: fix sg_page_count and sg_dma_page_count

by Julian Orth

On Sun, Mar 8, 2026 at 7:08 PM Jason Gunthorpe <jgg(a)ziepe.ca> wrote: > > On Sun, Mar 08, 2026 at 02:55:27PM +0100, Julian Orth wrote: > > A user reported memory corruption in the Jay wayland compositor [1]. The > > corruption started when archlinux enabled > > CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_WITHIN_SIZE in kernel 6.19.5. > > > > The compositor uses udmabuf to upload memory from memfds to the GPU. > > When running an affected kernel, the following warnings are logged: > > > > a - addrs >= max_entries > > WARNING: drivers/gpu/drm/drm_prime.c:1089 at drm_prime_sg_to_dma_addr_array+0x86/0xc0, CPU#31: jay/1864 > > [...] > > Call Trace: > > <TASK> > > amdgpu_bo_move+0x188/0x800 [amdgpu 3b451640234948027c09e9b39e6520bc7e5471cf] > > > > Disabling the use of huge pages at runtime via > > /sys/kernel/mm/transparent_hugepage/shmem_enabled fixes the issue. > > > > udmabuf allocates a scatterlist with buffer_size/PAGE_SIZE entries. Each > > entry has a length of PAGE_SIZE. With huge pages disabled, it appears > > that sg->offset is always 0. With huge pages enabled, sg->offset is > > incremented by PAGE_SIZE until the end of the huge page. > > This was broken by 0c8b91ef5100 ("udmabuf: add back support for > mapping hugetlb pages") which switched from a working > sg_alloc_table_from_pages() to a messed up sg_set_pages loop: > > + for_each_sg(sg->sgl, sgl, ubuf->pagecount, i) > + sg_set_page(sgl, ubuf->pages[i], PAGE_SIZE, ubuf->offsets[i]); > [..] > + ubuf->offsets[*pgbuf] = subpgoff << PAGE_SHIFT; > > Which is just the wrong way to use the scatterlist API. > > This was later changed to sg_set_folio() which I'm also suspecting has > a bug, it should be setting page_link to the proper tail page because > as you observe page_offset must fall within 0 to PAGE_SIZE-1 to make > the iterator work. > > I think the whole design here in udmabuf makes very little sense. It > starts out with an actual list of folios then expands them to a per-4K > double array of folio/offset. This is nonsensical, if it wants to > build a way to direct index the mapping for mmap it should just build > itself a page * array like the code used to do and continue to use > sg_alloc_table_from_pages() which builds properly formed scatterlists. > > This would save memory, use the APIs properly and build a correct and > optimized scatterlist to boot. It uses vmf_insert_pfn() and > vm_map_ram() anyhow so it doesn't even use a folio :\ > > Here, a few mins of AI shows what I think udmabuf should look like. If > you wish to persue this please add my signed-off-by and handle testing > it and getting it merged. I reviewed it enough to see it was showing > what I wanted. I don't know enough about folios or udmabuf to efficiently work on this. If offset is supposed to be in [0, PAGE_SIZE-1], then my patch is incorrect and it's probably better if some of the udmabuf maintainers take a look at this. I've added them to CC. > > Jason > > diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c > index 94b8ecb892bb17..5d687860445137 100644 > --- a/drivers/dma-buf/udmabuf.c > +++ b/drivers/dma-buf/udmabuf.c > @@ -26,10 +26,10 @@ MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is > > struct udmabuf { > pgoff_t pagecount; > - struct folio **folios; > + struct page **pages; > > /** > - * Unlike folios, pinned_folios is only used for unpin. > + * Unlike pages, pinned_folios is only used for unpin. > * So, nr_pinned is not the same to pagecount, the pinned_folios > * only set each folio which already pinned when udmabuf_create. > * Note that, since a folio may be pinned multiple times, each folio > @@ -41,7 +41,6 @@ struct udmabuf { > > struct sg_table *sg; > struct miscdevice *device; > - pgoff_t *offsets; > }; > > static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) > @@ -55,8 +54,7 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) > if (pgoff >= ubuf->pagecount) > return VM_FAULT_SIGBUS; > > - pfn = folio_pfn(ubuf->folios[pgoff]); > - pfn += ubuf->offsets[pgoff] >> PAGE_SHIFT; > + pfn = page_to_pfn(ubuf->pages[pgoff]); > > ret = vmf_insert_pfn(vma, vmf->address, pfn); > if (ret & VM_FAULT_ERROR) > @@ -73,8 +71,7 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) > if (WARN_ON(pgoff >= ubuf->pagecount)) > break; > > - pfn = folio_pfn(ubuf->folios[pgoff]); > - pfn += ubuf->offsets[pgoff] >> PAGE_SHIFT; > + pfn = page_to_pfn(ubuf->pages[pgoff]); > > /** > * If the below vmf_insert_pfn() fails, we do not return an > @@ -109,22 +106,11 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma) > static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map) > { > struct udmabuf *ubuf = buf->priv; > - struct page **pages; > void *vaddr; > - pgoff_t pg; > > dma_resv_assert_held(buf->resv); > > - pages = kvmalloc_objs(*pages, ubuf->pagecount); > - if (!pages) > - return -ENOMEM; > - > - for (pg = 0; pg < ubuf->pagecount; pg++) > - pages[pg] = folio_page(ubuf->folios[pg], > - ubuf->offsets[pg] >> PAGE_SHIFT); > - > - vaddr = vm_map_ram(pages, ubuf->pagecount, -1); > - kvfree(pages); > + vaddr = vm_map_ram(ubuf->pages, ubuf->pagecount, -1); > if (!vaddr) > return -EINVAL; > > @@ -146,22 +132,18 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, > { > struct udmabuf *ubuf = buf->priv; > struct sg_table *sg; > - struct scatterlist *sgl; > - unsigned int i = 0; > int ret; > > sg = kzalloc_obj(*sg); > if (!sg) > return ERR_PTR(-ENOMEM); > > - ret = sg_alloc_table(sg, ubuf->pagecount, GFP_KERNEL); > + ret = sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->pagecount, 0, > + ubuf->pagecount << PAGE_SHIFT, > + GFP_KERNEL); > if (ret < 0) > goto err_alloc; > > - for_each_sg(sg->sgl, sgl, ubuf->pagecount, i) > - sg_set_folio(sgl, ubuf->folios[i], PAGE_SIZE, > - ubuf->offsets[i]); > - > ret = dma_map_sgtable(dev, sg, direction, 0); > if (ret < 0) > goto err_map; > @@ -207,12 +189,8 @@ static void unpin_all_folios(struct udmabuf *ubuf) > > static __always_inline int init_udmabuf(struct udmabuf *ubuf, pgoff_t pgcnt) > { > - ubuf->folios = kvmalloc_objs(*ubuf->folios, pgcnt); > - if (!ubuf->folios) > - return -ENOMEM; > - > - ubuf->offsets = kvzalloc_objs(*ubuf->offsets, pgcnt); > - if (!ubuf->offsets) > + ubuf->pages = kvmalloc_objs(*ubuf->pages, pgcnt); > + if (!ubuf->pages) > return -ENOMEM; > > ubuf->pinned_folios = kvmalloc_objs(*ubuf->pinned_folios, pgcnt); > @@ -225,8 +203,7 @@ static __always_inline int init_udmabuf(struct udmabuf *ubuf, pgoff_t pgcnt) > static __always_inline void deinit_udmabuf(struct udmabuf *ubuf) > { > unpin_all_folios(ubuf); > - kvfree(ubuf->offsets); > - kvfree(ubuf->folios); > + kvfree(ubuf->pages); > } > > static void release_udmabuf(struct dma_buf *buf) > @@ -344,8 +321,8 @@ static long udmabuf_pin_folios(struct udmabuf *ubuf, struct file *memfd, > ubuf->pinned_folios[nr_pinned++] = folios[cur_folio]; > > for (; subpgoff < fsize; subpgoff += PAGE_SIZE) { > - ubuf->folios[upgcnt] = folios[cur_folio]; > - ubuf->offsets[upgcnt] = subpgoff; > + ubuf->pages[upgcnt] = folio_page(folios[cur_folio], > + subpgoff >> PAGE_SHIFT); > ++upgcnt; > > if (++cur_pgcnt >= pgcnt) >

7 months, 3 weeks

[PATCH v2 0/2] dma-buf: heaps: Use page clearing helpers

by Linus Walleij

Use clear_pages() and clear_highpage() properly in the DMA heap allocator. Signed-off-by: Linus Walleij <linusw(a)kernel.org> --- Changes in v2: - Added a second patch to use the clear_highpage() helper. - Link to v1: https://lore.kernel.org/r/20260304-cma-heap-clear-pages-v1-1-6ff59da716d3@k… --- Linus Walleij (2): dma-buf: heaps: Clear CMA pages with clear_pages() dma-buf: heaps: Clear CMA highages using helper drivers/dma-buf/heaps/cma_heap.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) --- base-commit: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f change-id: 20260303-cma-heap-clear-pages-540f3ac9f734 Best regards, -- Linus Walleij <linusw(a)kernel.org>

7 months, 3 weeks

[syzbot] [media?] [dri?] KASAN: slab-use-after-free Read in dma_buf_fd

by syzbot

Hello, syzbot found the following issue on: HEAD commit: 5ee8dbf54602 Merge tag 'fsverity-for-linus' of git://git.k.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=143e4a02580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2a019678b1a3a692 dashboard link: https://syzkaller.appspot.com/bug?extid=7f4987d0afb97dd090cb compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8f3ca4731c70/disk-5ee8dbf5.raw… vmlinux: https://storage.googleapis.com/syzbot-assets/9e6d67fcdf59/vmlinux-5ee8dbf5.… kernel image: https://storage.googleapis.com/syzbot-assets/dd6699ad586c/bzImage-5ee8dbf5.… IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+7f4987d0afb97dd090cb(a)syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162 Read of size 1 at addr ffff888034d9c068 by task syz.6.794/10028 CPU: 1 UID: 0 PID: 10028 Comm: syz.6.794 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire+0x79/0x2e0 kernel/locking/lockdep.c:5842 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162 rt_mutex_slowunlock+0xbf/0x8b0 kernel/locking/rtmutex.c:1417 spin_unlock include/linux/spinlock_rt.h:109 [inline] class_spinlock_destructor include/linux/spinlock.h:586 [inline] dma_buf_fd+0x189/0x370 drivers/dma-buf/dma-buf.c:796 vb2_core_expbuf+0x37e/0x620 drivers/media/common/videobuf2/videobuf2-core.c:2471 __video_do_ioctl+0x88c/0xc50 drivers/media/v4l2-core/v4l2-ioctl.c:3132 video_usercopy+0x876/0x14b0 drivers/media/v4l2-core/v4l2-ioctl.c:3474 v4l2_ioctl+0x190/0x1e0 drivers/media/v4l2-core/v4l2-dev.c:366 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa4633cc799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa46161e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa463645fa0 RCX: 00007fa4633cc799 RDX: 0000200000000040 RSI: 00000000c0405610 RDI: 0000000000000004 RBP: 00007fa463462bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa463646038 R14: 00007fa463645fa0 R15: 00007ffe4429d3d8 </TASK> Allocated by task 10028: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5238 [inline] __kmalloc_noprof+0x3e7/0x7b0 mm/slub.c:5250 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] dma_buf_export+0x3ba/0xb10 drivers/dma-buf/dma-buf.c:739 vb2_vmalloc_get_dmabuf+0x10e/0x210 drivers/media/common/videobuf2/videobuf2-vmalloc.c:352 vb2_core_expbuf+0x314/0x620 drivers/media/common/videobuf2/videobuf2-core.c:2461 __video_do_ioctl+0x88c/0xc50 drivers/media/v4l2-core/v4l2-ioctl.c:3132 video_usercopy+0x876/0x14b0 drivers/media/v4l2-core/v4l2-ioctl.c:3474 v4l2_ioctl+0x190/0x1e0 drivers/media/v4l2-core/v4l2-dev.c:366 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 10031: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2692 [inline] slab_free mm/slub.c:6143 [inline] kfree+0x1c1/0x6c0 mm/slub.c:6461 __dentry_kill+0x211/0x5e0 fs/dcache.c:675 finish_dput+0xc9/0x480 fs/dcache.c:879 __fput+0x6a3/0xa90 fs/file_table.c:477 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888034d9c000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 104 bytes inside of freed 1024-byte region [ffff888034d9c000, ffff888034d9c400) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34d98 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813fe1cdc0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe1cdc0 dead000000000100 dead000000000122 head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0000d36601 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6221, tgid 6216 (syz.3.71), ts 173025510293, free_ts 172769017733 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3269 [inline] allocate_slab+0x77/0x660 mm/slub.c:3458 new_slab mm/slub.c:3516 [inline] refill_objects+0x334/0x3c0 mm/slub.c:7153 refill_sheaf mm/slub.c:2818 [inline] __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4592 alloc_from_pcs mm/slub.c:4695 [inline] slab_alloc_node mm/slub.c:4829 [inline] __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5353 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] snd_seq_oss_open+0x125/0xfc0 sound/core/seq/oss/seq_oss_init.c:171 odev_open+0x67/0xd0 sound/core/seq/oss/seq_oss.c:128 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:411 do_dentry_open+0x83d/0x13e0 fs/open.c:949 vfs_open+0x3b/0x350 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e43/0x38a0 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 page last free pid 6219 tgid 6219 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xfe3/0x1170 mm/page_alloc.c:2978 __slab_free+0x24f/0x2a0 mm/slub.c:5551 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4515 [inline] slab_alloc_node mm/slub.c:4844 [inline] kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4851 vm_area_dup+0x2b/0x670 mm/vma_init.c:123 __split_vma+0x1e4/0xa30 mm/vma.c:513 split_vma mm/vma.c:596 [inline] vma_modify+0x94b/0x1f00 mm/vma.c:1672 vma_modify_flags+0x24b/0x330 mm/vma.c:1700 mprotect_fixup+0x47a/0xa80 mm/mprotect.c:756 do_mprotect_pkey+0x8ab/0xcd0 mm/mprotect.c:930 __do_sys_mprotect mm/mprotect.c:951 [inline] __se_sys_mprotect mm/mprotect.c:948 [inline] __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:948 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888034d9bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888034d9bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888034d9c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888034d9c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888034d9c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller(a)googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup

7 months, 3 weeks

[PATCH] dma-buf: heaps: Clear CMA pages with clear_pages()

by Linus Walleij

As of commit 62a9f5a85b98 "mm: introduce clear_pages() and clear_user_pages()" we can clear a range of pages with a potentially assembly-optimized call. Instead of using a memset, use this helper to clear the whole range of pages from the CMA allocation. Signed-off-by: Linus Walleij <linusw(a)kernel.org> --- drivers/dma-buf/heaps/cma_heap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index bd3370b9a3f6..f0bacf25ed9d 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -343,7 +343,7 @@ static struct dma_buf *cma_heap_allocate(struct dma_heap *heap, nr_clear_pages--; } } else { - memset(page_address(cma_pages), 0, size); + clear_pages(page_address(cma_pages), pagecount); } buffer->pages = kmalloc_objs(*buffer->pages, pagecount); --- base-commit: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f change-id: 20260303-cma-heap-clear-pages-540f3ac9f734 Best regards, -- Linus Walleij <linusw(a)kernel.org>

7 months, 3 weeks

[PATCH v3 00/12] vfs: change inode->i_ino from unsigned long to u64

by Jeff Layton

7 months, 3 weeks

[PATCH v2 00/12] media: stm32: dcmi: stability & performance enhancements

by Alain Volmat

This series improve stability of the capture by fixing the handling of the overrun which was leading to captured frame corruption. Locking within the driver is also simplified and the way DMA is handled is reworked allowing to avoid having a specific handling for the JPEG data. Performances of capture can now be increased via the usage of a DMA->MDMA chaining which allows for capture of higher resolution / framerate. Signed-off-by: Alain Volmat <alain.volmat(a)foss.st.com> --- Changes in v2: - Fix pm_sleep_ptr -> pm_ptr to avoid unused function warning - Fix typo / remove useless comment in binding - Link to v1: https://lore.kernel.org/r/20251218-stm32-dcmi-dma-chaining-v1-0-39948ca6cbf… --- Alain Volmat (12): media: stm32: dcmi: Switch from __maybe_unused to pm_ptr() media: stm32: dcmi: perform dmaengine_slave_config at probe media: stm32: dcmi: only create dma descriptor once at buf_prepare media: stm32: dcmi: stop the dma transfer on overrun media: stm32: dcmi: rework spin_lock calls media: stm32: dcmi: perform all dma handling within irq_thread media: stm32: dcmi: use dmaengine_terminate_async in irq context media: stm32: dcmi: continuous mode capture in JPEG dt-bindings: media: st: dcmi: add DMA-MDMA chaining properties media: stm32: dcmi: addition of DMA-MDMA chaining support ARM: dts: stm32: add sram node within stm32mp151.dtsi ARM: dts: stm32: enable DCMI DMA-MDMA chaining on stm32mp157c-ev1.dts .../devicetree/bindings/media/st,stm32-dcmi.yaml | 11 +- arch/arm/boot/dts/st/stm32mp151.dtsi | 8 + arch/arm/boot/dts/st/stm32mp157c-ev1.dts | 15 + drivers/media/platform/st/stm32/stm32-dcmi.c | 475 +++++++++++++-------- 4 files changed, 341 insertions(+), 168 deletions(-) --- base-commit: f7231cff1f3ff8259bef02dc4999bc132abf29cf change-id: 20251213-stm32-dcmi-dma-chaining-9ea1da83007d Best regards, -- Alain Volmat <alain.volmat(a)foss.st.com>

7 months, 4 weeks

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Linaro-mm-sig March 2026