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[PATCH v5 4/4] ring-buffer: Use flush_kernel_vmap_range() over flush_dcache_folio()

by Steven Rostedt

From: Steven Rostedt <rostedt(a)goodmis.org> Some architectures do not have data cache coherency between user and kernel space. For these architectures, the cache needs to be flushed on both the kernel and user addresses so that user space can see the updates the kernel has made. Instead of using flush_dcache_folio() and playing with virt_to_folio() within the call to that function, use flush_kernel_vmap_range() which takes the virtual address and does the work for those architectures that need it. This also fixes a bug where the flush of the reader page only flushed one page. If the sub-buffer order is 1 or more, where the sub-buffer size would be greater than a page, it would miss the rest of the sub-buffer content, as the "reader page" is not just a page, but the size of a sub-buffer. Link: https://lore.kernel.org/all/CAG48ez3w0my4Rwttbc5tEbNsme6tc0mrSN95thjXUFaJ3a… Cc: stable(a)vger.kernel.org Fixes: 117c39200d9d7 ("ring-buffer: Introducing ring-buffer mapping functions"); Suggested-by: Jann Horn <jannh(a)google.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index d8d7b28e2c2f..c0f877d39a24 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6016,7 +6016,7 @@ static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer) meta->read = cpu_buffer->read; /* Some archs do not have data cache coherency between kernel and user-space */ - flush_dcache_folio(virt_to_folio(cpu_buffer->meta_page)); + flush_kernel_vmap_range(cpu_buffer->meta_page, PAGE_SIZE); } static void @@ -7319,7 +7319,8 @@ int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu) out: /* Some archs do not have data cache coherency between kernel and user-space */ - flush_dcache_folio(virt_to_folio(cpu_buffer->reader_page->page)); + flush_kernel_vmap_range(cpu_buffer->reader_page->page, + buffer->subbuf_size + BUF_PAGE_HDR_SIZE); rb_update_meta_page(cpu_buffer); -- 2.47.2

3 months

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[merged mm-nonmm-stable] lib-scatterlist-fix-sg_split_phys-to-preserve-original-scatterlist-offsets.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: lib: scatterlist: fix sg_split_phys to preserve original scatterlist offsets has been removed from the -mm tree. Its filename was lib-scatterlist-fix-sg_split_phys-to-preserve-original-scatterlist-offsets.patch This patch was dropped because it was merged into the mm-nonmm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: T Pratham <t-pratham(a)ti.com> Subject: lib: scatterlist: fix sg_split_phys to preserve original scatterlist offsets Date: Wed, 19 Mar 2025 16:44:38 +0530 The split_sg_phys function was incorrectly setting the offsets of all scatterlist entries (except the first) to 0. Only the first scatterlist entry's offset and length needs to be modified to account for the skip. Setting the rest entries' offsets to 0 could lead to incorrect data access. I am using this function in a crypto driver that I'm currently developing (not yet sent to mailing list). During testing, it was observed that the output scatterlists (except the first one) contained incorrect garbage data. I narrowed this issue down to the call of sg_split(). Upon debugging inside this function, I found that this resetting of offset is the cause of the problem, causing the subsequent scatterlists to point to incorrect memory locations in a page. By removing this code, I am obtaining expected data in all the split output scatterlists. Thus, this was indeed causing observable runtime effects! This patch removes the offending code, ensuring that the page offsets in the input scatterlist are preserved in the output scatterlist. Link: https://lkml.kernel.org/r/20250319111437.1969903-1-t-pratham@ti.com Fixes: f8bcbe62acd0 ("lib: scatterlist: add sg splitting function") Signed-off-by: T Pratham <t-pratham(a)ti.com> Cc: Robert Jarzmik <robert.jarzmik(a)free.fr> Cc: Jens Axboe <axboe(a)kernel.dk> Cc: Kamlesh Gurudasani <kamlesh(a)ti.com> Cc: Praneeth Bajjuri <praneeth(a)ti.com> Cc: Vignesh Raghavendra <vigneshr(a)ti.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- lib/sg_split.c | 2 -- 1 file changed, 2 deletions(-) --- a/lib/sg_split.c~lib-scatterlist-fix-sg_split_phys-to-preserve-original-scatterlist-offsets +++ a/lib/sg_split.c @@ -88,8 +88,6 @@ static void sg_split_phys(struct sg_spli if (!j) { out_sg->offset += split->skip_sg0; out_sg->length -= split->skip_sg0; - } else { - out_sg->offset = 0; } sg_dma_address(out_sg) = 0; sg_dma_len(out_sg) = 0; _ Patches currently in -mm which might be from t-pratham(a)ti.com are

3 months

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[merged mm-hotfixes-stable] mm-zswap-fix-crypto_free_acomp-deadlock-in-zswap_cpu_comp_dead.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm: zswap: fix crypto_free_acomp() deadlock in zswap_cpu_comp_dead() has been removed from the -mm tree. Its filename was mm-zswap-fix-crypto_free_acomp-deadlock-in-zswap_cpu_comp_dead.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Yosry Ahmed <yosry.ahmed(a)linux.dev> Subject: mm: zswap: fix crypto_free_acomp() deadlock in zswap_cpu_comp_dead() Date: Wed, 26 Feb 2025 18:56:25 +0000 Currently, zswap_cpu_comp_dead() calls crypto_free_acomp() while holding the per-CPU acomp_ctx mutex. crypto_free_acomp() then holds scomp_lock (through crypto_exit_scomp_ops_async()). On the other hand, crypto_alloc_acomp_node() holds the scomp_lock (through crypto_scomp_init_tfm()), and then allocates memory. If the allocation results in reclaim, we may attempt to hold the per-CPU acomp_ctx mutex. The above dependencies can cause an ABBA deadlock. For example in the following scenario: (1) Task A running on CPU #1: crypto_alloc_acomp_node() Holds scomp_lock Enters reclaim Reads per_cpu_ptr(pool->acomp_ctx, 1) (2) Task A is descheduled (3) CPU #1 goes offline zswap_cpu_comp_dead(CPU #1) Holds per_cpu_ptr(pool->acomp_ctx, 1)) Calls crypto_free_acomp() Waits for scomp_lock (4) Task A running on CPU #2: Waits for per_cpu_ptr(pool->acomp_ctx, 1) // Read on CPU #1 DEADLOCK Since there is no requirement to call crypto_free_acomp() with the per-CPU acomp_ctx mutex held in zswap_cpu_comp_dead(), move it after the mutex is unlocked. Also move the acomp_request_free() and kfree() calls for consistency and to avoid any potential sublte locking dependencies in the future. With this, only setting acomp_ctx fields to NULL occurs with the mutex held. This is similar to how zswap_cpu_comp_prepare() only initializes acomp_ctx fields with the mutex held, after performing all allocations before holding the mutex. Opportunistically, move the NULL check on acomp_ctx so that it takes place before the mutex dereference. Link: https://lkml.kernel.org/r/20250226185625.2672936-1-yosry.ahmed@linux.dev Fixes: 12dcb0ef5406 ("mm: zswap: properly synchronize freeing resources during CPU hotunplug") Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au> Co-developed-by: Herbert Xu <herbert(a)gondor.apana.org.au> Signed-off-by: Yosry Ahmed <yosry.ahmed(a)linux.dev> Reported-by: syzbot+1a517ccfcbc6a7ab0f82(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67bcea51.050a0220.bbfd1.0096.GAE@google.com/ Acked-by: Herbert Xu <herbert(a)gondor.apana.org.au> Reviewed-by: Chengming Zhou <chengming.zhou(a)linux.dev> Reviewed-by: Nhat Pham <nphamcs(a)gmail.com> Tested-by: Nhat Pham <nphamcs(a)gmail.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Eric Biggers <ebiggers(a)kernel.org> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Chris Murphy <lists(a)colorremedies.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/zswap.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) --- a/mm/zswap.c~mm-zswap-fix-crypto_free_acomp-deadlock-in-zswap_cpu_comp_dead +++ a/mm/zswap.c @@ -883,18 +883,32 @@ static int zswap_cpu_comp_dead(unsigned { struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); struct crypto_acomp_ctx *acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu); + struct acomp_req *req; + struct crypto_acomp *acomp; + u8 *buffer; + + if (IS_ERR_OR_NULL(acomp_ctx)) + return 0; mutex_lock(&acomp_ctx->mutex); - if (!IS_ERR_OR_NULL(acomp_ctx)) { - if (!IS_ERR_OR_NULL(acomp_ctx->req)) - acomp_request_free(acomp_ctx->req); - acomp_ctx->req = NULL; - if (!IS_ERR_OR_NULL(acomp_ctx->acomp)) - crypto_free_acomp(acomp_ctx->acomp); - kfree(acomp_ctx->buffer); - } + req = acomp_ctx->req; + acomp = acomp_ctx->acomp; + buffer = acomp_ctx->buffer; + acomp_ctx->req = NULL; + acomp_ctx->acomp = NULL; + acomp_ctx->buffer = NULL; mutex_unlock(&acomp_ctx->mutex); + /* + * Do the actual freeing after releasing the mutex to avoid subtle + * locking dependencies causing deadlocks. + */ + if (!IS_ERR_OR_NULL(req)) + acomp_request_free(req); + if (!IS_ERR_OR_NULL(acomp)) + crypto_free_acomp(acomp); + kfree(buffer); + return 0; } _ Patches currently in -mm which might be from yosry.ahmed(a)linux.dev are

3 months

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[merged mm-hotfixes-stable] mm-hugetlb-move-hugetlb_sysctl_init-to-the-__init-section.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/hugetlb: move hugetlb_sysctl_init() to the __init section has been removed from the -mm tree. Its filename was mm-hugetlb-move-hugetlb_sysctl_init-to-the-__init-section.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Marc Herbert <Marc.Herbert(a)linux.intel.com> Subject: mm/hugetlb: move hugetlb_sysctl_init() to the __init section Date: Wed, 19 Mar 2025 06:00:30 +0000 hugetlb_sysctl_init() is only invoked once by an __init function and is merely a wrapper around another __init function so there is not reason to keep it. Fixes the following warning when toning down some GCC inline options: WARNING: modpost: vmlinux: section mismatch in reference: hugetlb_sysctl_init+0x1b (section: .text) -> __register_sysctl_init (section: .init.text) Link: https://lkml.kernel.org/r/20250319060041.2737320-1-marc.herbert@linux.intel… Signed-off-by: Marc Herbert <Marc.Herbert(a)linux.intel.com> Reviewed-by: Anshuman Khandual <anshuman.khandual(a)arm.com> Reviewed-by: Muchun Song <muchun.song(a)linux.dev> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/hugetlb.c~mm-hugetlb-move-hugetlb_sysctl_init-to-the-__init-section +++ a/mm/hugetlb.c @@ -5179,7 +5179,7 @@ static const struct ctl_table hugetlb_ta }, }; -static void hugetlb_sysctl_init(void) +static void __init hugetlb_sysctl_init(void) { register_sysctl_init("vm", hugetlb_table); } _ Patches currently in -mm which might be from Marc.Herbert(a)linux.intel.com are

3 months

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[merged mm-hotfixes-stable] mm-userfaultfd-fix-release-hang-over-concurrent-gup.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/userfaultfd: fix release hang over concurrent GUP has been removed from the -mm tree. Its filename was mm-userfaultfd-fix-release-hang-over-concurrent-gup.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Peter Xu <peterx(a)redhat.com> Subject: mm/userfaultfd: fix release hang over concurrent GUP Date: Wed, 12 Mar 2025 10:51:31 -0400 This patch should fix a possible userfaultfd release() hang during concurrent GUP. This problem was initially reported by Dimitris Siakavaras in July 2023 [1] in a firecracker use case. Firecracker has a separate process handling page faults remotely, and when the process releases the userfaultfd it can race with a concurrent GUP from KVM trying to fault in a guest page during the secondary MMU page fault process. A similar problem was reported recently again by Jinjiang Tu in March 2025 [2], even though the race happened this time with a mlockall() operation, which does GUP in a similar fashion. In 2017, commit 656710a60e36 ("userfaultfd: non-cooperative: closing the uffd without triggering SIGBUS") was trying to fix this issue. AFAIU, that fixes well the fault paths but may not work yet for GUP. In GUP, the issue is NOPAGE will be almost treated the same as "page fault resolved" in faultin_page(), then the GUP will follow page again, seeing page missing, and it'll keep going into a live lock situation as reported. This change makes core mm return RETRY instead of NOPAGE for both the GUP and fault paths, proactively releasing the mmap read lock. This should guarantee the other release thread make progress on taking the write lock and avoid the live lock even for GUP. When at it, rearrange the comments to make sure it's uptodate. [1] https://lore.kernel.org/r/79375b71-db2e-3e66-346b-254c90d915e2@cslab.ece.nt… [2] https://lore.kernel.org/r/20250307072133.3522652-1-tujinjiang@huawei.com Link: https://lkml.kernel.org/r/20250312145131.1143062-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx(a)redhat.com> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Cc: Mike Rapoport (IBM) <rppt(a)kernel.org> Cc: Axel Rasmussen <axelrasmussen(a)google.com> Cc: Jinjiang Tu <tujinjiang(a)huawei.com> Cc: Dimitris Siakavaras <jimsiak(a)cslab.ece.ntua.gr> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/userfaultfd.c | 51 ++++++++++++++++++++++----------------------- 1 file changed, 25 insertions(+), 26 deletions(-) --- a/fs/userfaultfd.c~mm-userfaultfd-fix-release-hang-over-concurrent-gup +++ a/fs/userfaultfd.c @@ -396,32 +396,6 @@ vm_fault_t handle_userfault(struct vm_fa goto out; /* - * If it's already released don't get it. This avoids to loop - * in __get_user_pages if userfaultfd_release waits on the - * caller of handle_userfault to release the mmap_lock. - */ - if (unlikely(READ_ONCE(ctx->released))) { - /* - * Don't return VM_FAULT_SIGBUS in this case, so a non - * cooperative manager can close the uffd after the - * last UFFDIO_COPY, without risking to trigger an - * involuntary SIGBUS if the process was starting the - * userfaultfd while the userfaultfd was still armed - * (but after the last UFFDIO_COPY). If the uffd - * wasn't already closed when the userfault reached - * this point, that would normally be solved by - * userfaultfd_must_wait returning 'false'. - * - * If we were to return VM_FAULT_SIGBUS here, the non - * cooperative manager would be instead forced to - * always call UFFDIO_UNREGISTER before it can safely - * close the uffd. - */ - ret = VM_FAULT_NOPAGE; - goto out; - } - - /* * Check that we can return VM_FAULT_RETRY. * * NOTE: it should become possible to return VM_FAULT_RETRY @@ -457,6 +431,31 @@ vm_fault_t handle_userfault(struct vm_fa if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT) goto out; + if (unlikely(READ_ONCE(ctx->released))) { + /* + * If a concurrent release is detected, do not return + * VM_FAULT_SIGBUS or VM_FAULT_NOPAGE, but instead always + * return VM_FAULT_RETRY with lock released proactively. + * + * If we were to return VM_FAULT_SIGBUS here, the non + * cooperative manager would be instead forced to + * always call UFFDIO_UNREGISTER before it can safely + * close the uffd, to avoid involuntary SIGBUS triggered. + * + * If we were to return VM_FAULT_NOPAGE, it would work for + * the fault path, in which the lock will be released + * later. However for GUP, faultin_page() does nothing + * special on NOPAGE, so GUP would spin retrying without + * releasing the mmap read lock, causing possible livelock. + * + * Here only VM_FAULT_RETRY would make sure the mmap lock + * be released immediately, so that the thread concurrently + * releasing the userfault would always make progress. + */ + release_fault_lock(vmf); + goto out; + } + /* take the reference before dropping the mmap_lock */ userfaultfd_ctx_get(ctx); _ Patches currently in -mm which might be from peterx(a)redhat.com are maintainers-add-myself-as-userfaultfd-reviewer.patch

3 months

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[to-be-updated] x86-vmemmap-use-direct-mapped-va-instead-of-vmemmap-based-va.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: x86/vmemmap: use direct-mapped VA instead of vmemmap-based VA has been removed from the -mm tree. Its filename was x86-vmemmap-use-direct-mapped-va-instead-of-vmemmap-based-va.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Gwan-gyeong Mun <gwan-gyeong.mun(a)intel.com> Subject: x86/vmemmap: use direct-mapped VA instead of vmemmap-based VA Date: Mon, 17 Feb 2025 13:41:33 +0200 Address an Oops issues when performing test of loading XE GPU driver module after applying the GPU SVM and Xe SVM patch series[1] and the Dept patch series[2]. The issue occurs when loading the xe driver via modprobe [3], which adds a struct page for device memory via devm_memremap_pages(). When a process leads the addition of a struct page to vmemmap (e.g. hot-plug), the page table update for the newly added vmemmap-based virtual address is updated first in init_mm's page table and then synchronized later. If the vmemmap-based virtual address is accessed through the process's page table before this sync, a page fault will occur. This patch translates vmemmap-based virtual address to direct-mapped virtual address and use it, if the current top-level page table is not init_mm's page table when accessing a vmemmap-based virtual address before this sync. [1] https://lore.kernel.org/dri-devel/20250213021112.1228481-1-matthew.brost@in… [2] https://lore.kernel.org/lkml/20240508094726.35754-1-byungchul@sk.com/ [3] [ 49.103630] xe 0000:00:04.0: [drm] Available VRAM: 0x0000000800000000, 0x00000002fb800000 [ 49.116710] BUG: unable to handle page fault for address: ffffeb3ff1200000 [ 49.117175] #PF: supervisor write access in kernel mode [ 49.117511] #PF: error_code(0x0002) - not-present page [ 49.117835] PGD 0 P4D 0 [ 49.118015] Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI [ 49.118366] CPU: 3 UID: 0 PID: 302 Comm: modprobe Tainted: G W 6.13.0-drm-tip-test+ #62 [ 49.118976] Tainted: [W]=WARN [ 49.119179] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 49.119710] RIP: 0010:vmemmap_set_pmd+0xff/0x230 [ 49.120011] Code: 77 22 02 a9 ff ff 1f 00 74 58 48 8b 3d 62 77 22 02 48 85 ff 0f 85 9a 00 00 00 48 8d 7d 08 48 89 e9 31 c0 48 89 ea 48 83 e7 f8 <48> c7 45 00 00 00 00 00 48 29 f9 48 c7 45 48 00 00 00 00 83 c1 50 [ 49.121158] RSP: 0018:ffffc900016d37a8 EFLAGS: 00010282 [ 49.121502] RAX: 0000000000000000 RBX: ffff888164000000 RCX: ffffeb3ff1200000 [ 49.121966] RDX: ffffeb3ff1200000 RSI: 80000000000001e3 RDI: ffffeb3ff1200008 [ 49.122499] RBP: ffffeb3ff1200000 R08: ffffeb3ff1280000 R09: 0000000000000000 [ 49.123032] R10: ffff88817b94dc48 R11: 0000000000000003 R12: ffffeb3ff1280000 [ 49.123566] R13: 0000000000000000 R14: ffff88817b94dc48 R15: 8000000163e001e3 [ 49.124096] FS: 00007f53ae71d740(0000) GS:ffff88843fd80000(0000) knlGS:0000000000000000 [ 49.124698] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.125129] CR2: ffffeb3ff1200000 CR3: 000000017c7d2000 CR4: 0000000000750ef0 [ 49.125662] PKRU: 55555554 [ 49.125880] Call Trace: [ 49.126078] <TASK> [ 49.126252] ? __die_body.cold+0x19/0x26 [ 49.126509] ? page_fault_oops+0xa2/0x240 [ 49.126736] ? preempt_count_add+0x47/0xa0 [ 49.126968] ? search_module_extables+0x4a/0x80 [ 49.127224] ? exc_page_fault+0x206/0x230 [ 49.127454] ? asm_exc_page_fault+0x22/0x30 [ 49.127691] ? vmemmap_set_pmd+0xff/0x230 [ 49.127919] vmemmap_populate_hugepages+0x176/0x180 [ 49.128194] vmemmap_populate+0x34/0x80 [ 49.128416] __populate_section_memmap+0x41/0x90 [ 49.128676] sparse_add_section+0x121/0x3e0 [ 49.128914] __add_pages+0xba/0x150 [ 49.129116] add_pages+0x1d/0x70 [ 49.129305] memremap_pages+0x3dc/0x810 [ 49.129529] devm_memremap_pages+0x1c/0x60 [ 49.129762] xe_devm_add+0x8b/0x100 [xe] [ 49.130072] xe_tile_init_noalloc+0x6a/0x70 [xe] [ 49.130408] xe_device_probe+0x48c/0x740 [xe] [ 49.130714] ? __pfx___drmm_mutex_release+0x10/0x10 [ 49.130982] ? __drmm_add_action+0x85/0xd0 [ 49.131208] ? __pfx___drmm_mutex_release+0x10/0x10 [ 49.131478] xe_pci_probe+0x7ef/0xd90 [xe] [ 49.131777] ? _raw_spin_unlock_irqrestore+0x66/0x90 [ 49.132049] ? lockdep_hardirqs_on+0xba/0x140 [ 49.132290] pci_device_probe+0x99/0x110 [ 49.132510] really_probe+0xdb/0x340 [ 49.132710] ? pm_runtime_barrier+0x50/0x90 [ 49.132941] ? __pfx___driver_attach+0x10/0x10 [ 49.133190] __driver_probe_device+0x78/0x110 [ 49.133433] driver_probe_device+0x1f/0xa0 [ 49.133661] __driver_attach+0xba/0x1c0 [ 49.133874] bus_for_each_dev+0x7a/0xd0 [ 49.134089] bus_add_driver+0x114/0x200 [ 49.134302] driver_register+0x6e/0xc0 [ 49.134515] xe_init+0x1e/0x50 [xe] [ 49.134827] ? __pfx_xe_init+0x10/0x10 [xe] [ 49.134926] xe 0000:00:04.0: [drm:process_one_work] GT1: GuC CT safe-mode canceled [ 49.135112] do_one_initcall+0x5b/0x2b0 [ 49.135734] ? rcu_is_watching+0xd/0x40 [ 49.135995] ? __kmalloc_cache_noprof+0x231/0x310 [ 49.136315] do_init_module+0x60/0x210 [ 49.136572] init_module_from_file+0x86/0xc0 [ 49.136863] idempotent_init_module+0x12b/0x340 [ 49.137156] __x64_sys_finit_module+0x61/0xc0 [ 49.137437] do_syscall_64+0x69/0x140 [ 49.137681] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 49.137953] RIP: 0033:0x7f53ae1261fd [ 49.138153] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 8b 0d e3 fa 0c 00 f7 d8 64 89 01 48 [ 49.139117] RSP: 002b:00007ffd0e9021e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 49.139525] RAX: ffffffffffffffda RBX: 000055c02951ee50 RCX: 00007f53ae1261fd [ 49.139905] RDX: 0000000000000000 RSI: 000055bfff125478 RDI: 0000000000000010 [ 49.140282] RBP: 000055bfff125478 R08: 00007f53ae1f6b20 R09: 00007ffd0e902230 [ 49.140663] R10: 000055c029522000 R11: 0000000000000246 R12: 0000000000040000 [ 49.141040] R13: 000055c02951ef80 R14: 0000000000000000 R15: 000055c029521fc0 [ 49.141424] </TASK> [ 49.141552] Modules linked in: xe(+) drm_ttm_helper gpu_sched drm_suballoc_helper drm_gpuvm drm_exec drm_gpusvm i2c_algo_bit drm_buddy video wmi ttm drm_display_helper drm_kms_helper crct10dif_pclmul crc32_pclmul i2c_piix4 e1000 ghash_clmulni_intel i2c_smbus fuse [ 49.142824] CR2: ffffeb3ff1200000 [ 49.143010] ---[ end trace 0000000000000000 ]--- [ 49.143268] RIP: 0010:vmemmap_set_pmd+0xff/0x230 [ 49.143523] Code: 77 22 02 a9 ff ff 1f 00 74 58 48 8b 3d 62 77 22 02 48 85 ff 0f 85 9a 00 00 00 48 8d 7d 08 48 89 e9 31 c0 48 89 ea 48 83 e7 f8 <48> c7 45 00 00 00 00 00 48 29 f9 48 c7 45 48 00 00 00 00 83 c1 50 [ 49.144489] RSP: 0018:ffffc900016d37a8 EFLAGS: 00010282 [ 49.144775] RAX: 0000000000000000 RBX: ffff888164000000 RCX: ffffeb3ff1200000 [ 49.145154] RDX: ffffeb3ff1200000 RSI: 80000000000001e3 RDI: ffffeb3ff1200008 [ 49.145536] RBP: ffffeb3ff1200000 R08: ffffeb3ff1280000 R09: 0000000000000000 [ 49.145914] R10: ffff88817b94dc48 R11: 0000000000000003 R12: ffffeb3ff1280000 [ 49.146292] R13: 0000000000000000 R14: ffff88817b94dc48 R15: 8000000163e001e3 [ 49.146671] FS: 00007f53ae71d740(0000) GS:ffff88843fd80000(0000) knlGS:0000000000000000 [ 49.147097] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.147407] CR2: ffffeb3ff1200000 CR3: 000000017c7d2000 CR4: 0000000000750ef0 [ 49.147786] PKRU: 55555554 [ 49.147941] note: modprobe[302] exited with irqs disabled When a process leads the addition of a struct page to vmemmap (e.g. hot-plug), the page table update for the newly added vmemmap-based virtual address is updated first in init_mm's page table and then synchronized later. If the vmemmap-based virtual address is accessed through the process's page table before this sync, a page fault will occur. This translates vmemmap-based virtual address to direct-mapped virtual address and use it, if the current top-level page table is not init_mm's page table when accessing a vmemmap-based virtual address before this sync. Link: https://lkml.kernel.org/r/20250217114133.400063-2-gwan-gyeong.mun@intel.com Fixes: faf1c0008a33 ("x86/vmemmap: optimize for consecutive sections in partial populated PMDs") Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun(a)intel.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Hyeonggon Yoo <42.hyeyoo(a)gmail.com> Cc: Byungchul Park <byungchul(a)sk.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- arch/x86/mm/init_64.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) --- a/arch/x86/mm/init_64.c~x86-vmemmap-use-direct-mapped-va-instead-of-vmemmap-based-va +++ a/arch/x86/mm/init_64.c @@ -844,6 +844,17 @@ void __init paging_init(void) */ static unsigned long unused_pmd_start __meminitdata; +static void * __meminit vmemmap_va_to_kaddr(unsigned long vmemmap_va) +{ + void *kaddr = (void *)vmemmap_va; + pgd_t *pgd = __va(read_cr3_pa()); + + if (init_mm.pgd != pgd) + kaddr = __va(slow_virt_to_phys(kaddr)); + + return kaddr; +} + static void __meminit vmemmap_flush_unused_pmd(void) { if (!unused_pmd_start) @@ -851,7 +862,7 @@ static void __meminit vmemmap_flush_unus /* * Clears (unused_pmd_start, PMD_END] */ - memset((void *)unused_pmd_start, PAGE_UNUSED, + memset(vmemmap_va_to_kaddr(unused_pmd_start), PAGE_UNUSED, ALIGN(unused_pmd_start, PMD_SIZE) - unused_pmd_start); unused_pmd_start = 0; } @@ -882,7 +893,7 @@ static void __meminit __vmemmap_use_sub_ * case the first memmap never gets initialized e.g., because the memory * block never gets onlined). */ - memset((void *)start, 0, sizeof(struct page)); + memset(vmemmap_va_to_kaddr(start), 0, sizeof(struct page)); } static void __meminit vmemmap_use_sub_pmd(unsigned long start, unsigned long end) @@ -924,7 +935,7 @@ static void __meminit vmemmap_use_new_su * Mark with PAGE_UNUSED the unused parts of the new memmap range */ if (!IS_ALIGNED(start, PMD_SIZE)) - memset((void *)page, PAGE_UNUSED, start - page); + memset(vmemmap_va_to_kaddr(page), PAGE_UNUSED, start - page); /* * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of _ Patches currently in -mm which might be from gwan-gyeong.mun(a)intel.com are

3 months

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+ x86-vmemmap-use-direct-mapped-va-instead-of-vmemmap-based-va.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: x86/vmemmap: use direct-mapped VA instead of vmemmap-based VA has been added to the -mm mm-hotfixes-unstable branch. Its filename is x86-vmemmap-use-direct-mapped-va-instead-of-vmemmap-based-va.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Gwan-gyeong Mun <gwan-gyeong.mun(a)intel.com> Subject: x86/vmemmap: use direct-mapped VA instead of vmemmap-based VA Date: Mon, 17 Feb 2025 13:41:33 +0200 Address an Oops issues when performing test of loading XE GPU driver module after applying the GPU SVM and Xe SVM patch series[1] and the Dept patch series[2]. The issue occurs when loading the xe driver via modprobe [3], which adds a struct page for device memory via devm_memremap_pages(). When a process leads the addition of a struct page to vmemmap (e.g. hot-plug), the page table update for the newly added vmemmap-based virtual address is updated first in init_mm's page table and then synchronized later. If the vmemmap-based virtual address is accessed through the process's page table before this sync, a page fault will occur. This patch translates vmemmap-based virtual address to direct-mapped virtual address and use it, if the current top-level page table is not init_mm's page table when accessing a vmemmap-based virtual address before this sync. [1] https://lore.kernel.org/dri-devel/20250213021112.1228481-1-matthew.brost@in… [2] https://lore.kernel.org/lkml/20240508094726.35754-1-byungchul@sk.com/ [3] [ 49.103630] xe 0000:00:04.0: [drm] Available VRAM: 0x0000000800000000, 0x00000002fb800000 [ 49.116710] BUG: unable to handle page fault for address: ffffeb3ff1200000 [ 49.117175] #PF: supervisor write access in kernel mode [ 49.117511] #PF: error_code(0x0002) - not-present page [ 49.117835] PGD 0 P4D 0 [ 49.118015] Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI [ 49.118366] CPU: 3 UID: 0 PID: 302 Comm: modprobe Tainted: G W 6.13.0-drm-tip-test+ #62 [ 49.118976] Tainted: [W]=WARN [ 49.119179] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 49.119710] RIP: 0010:vmemmap_set_pmd+0xff/0x230 [ 49.120011] Code: 77 22 02 a9 ff ff 1f 00 74 58 48 8b 3d 62 77 22 02 48 85 ff 0f 85 9a 00 00 00 48 8d 7d 08 48 89 e9 31 c0 48 89 ea 48 83 e7 f8 <48> c7 45 00 00 00 00 00 48 29 f9 48 c7 45 48 00 00 00 00 83 c1 50 [ 49.121158] RSP: 0018:ffffc900016d37a8 EFLAGS: 00010282 [ 49.121502] RAX: 0000000000000000 RBX: ffff888164000000 RCX: ffffeb3ff1200000 [ 49.121966] RDX: ffffeb3ff1200000 RSI: 80000000000001e3 RDI: ffffeb3ff1200008 [ 49.122499] RBP: ffffeb3ff1200000 R08: ffffeb3ff1280000 R09: 0000000000000000 [ 49.123032] R10: ffff88817b94dc48 R11: 0000000000000003 R12: ffffeb3ff1280000 [ 49.123566] R13: 0000000000000000 R14: ffff88817b94dc48 R15: 8000000163e001e3 [ 49.124096] FS: 00007f53ae71d740(0000) GS:ffff88843fd80000(0000) knlGS:0000000000000000 [ 49.124698] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.125129] CR2: ffffeb3ff1200000 CR3: 000000017c7d2000 CR4: 0000000000750ef0 [ 49.125662] PKRU: 55555554 [ 49.125880] Call Trace: [ 49.126078] <TASK> [ 49.126252] ? __die_body.cold+0x19/0x26 [ 49.126509] ? page_fault_oops+0xa2/0x240 [ 49.126736] ? preempt_count_add+0x47/0xa0 [ 49.126968] ? search_module_extables+0x4a/0x80 [ 49.127224] ? exc_page_fault+0x206/0x230 [ 49.127454] ? asm_exc_page_fault+0x22/0x30 [ 49.127691] ? vmemmap_set_pmd+0xff/0x230 [ 49.127919] vmemmap_populate_hugepages+0x176/0x180 [ 49.128194] vmemmap_populate+0x34/0x80 [ 49.128416] __populate_section_memmap+0x41/0x90 [ 49.128676] sparse_add_section+0x121/0x3e0 [ 49.128914] __add_pages+0xba/0x150 [ 49.129116] add_pages+0x1d/0x70 [ 49.129305] memremap_pages+0x3dc/0x810 [ 49.129529] devm_memremap_pages+0x1c/0x60 [ 49.129762] xe_devm_add+0x8b/0x100 [xe] [ 49.130072] xe_tile_init_noalloc+0x6a/0x70 [xe] [ 49.130408] xe_device_probe+0x48c/0x740 [xe] [ 49.130714] ? __pfx___drmm_mutex_release+0x10/0x10 [ 49.130982] ? __drmm_add_action+0x85/0xd0 [ 49.131208] ? __pfx___drmm_mutex_release+0x10/0x10 [ 49.131478] xe_pci_probe+0x7ef/0xd90 [xe] [ 49.131777] ? _raw_spin_unlock_irqrestore+0x66/0x90 [ 49.132049] ? lockdep_hardirqs_on+0xba/0x140 [ 49.132290] pci_device_probe+0x99/0x110 [ 49.132510] really_probe+0xdb/0x340 [ 49.132710] ? pm_runtime_barrier+0x50/0x90 [ 49.132941] ? __pfx___driver_attach+0x10/0x10 [ 49.133190] __driver_probe_device+0x78/0x110 [ 49.133433] driver_probe_device+0x1f/0xa0 [ 49.133661] __driver_attach+0xba/0x1c0 [ 49.133874] bus_for_each_dev+0x7a/0xd0 [ 49.134089] bus_add_driver+0x114/0x200 [ 49.134302] driver_register+0x6e/0xc0 [ 49.134515] xe_init+0x1e/0x50 [xe] [ 49.134827] ? __pfx_xe_init+0x10/0x10 [xe] [ 49.134926] xe 0000:00:04.0: [drm:process_one_work] GT1: GuC CT safe-mode canceled [ 49.135112] do_one_initcall+0x5b/0x2b0 [ 49.135734] ? rcu_is_watching+0xd/0x40 [ 49.135995] ? __kmalloc_cache_noprof+0x231/0x310 [ 49.136315] do_init_module+0x60/0x210 [ 49.136572] init_module_from_file+0x86/0xc0 [ 49.136863] idempotent_init_module+0x12b/0x340 [ 49.137156] __x64_sys_finit_module+0x61/0xc0 [ 49.137437] do_syscall_64+0x69/0x140 [ 49.137681] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 49.137953] RIP: 0033:0x7f53ae1261fd [ 49.138153] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 8b 0d e3 fa 0c 00 f7 d8 64 89 01 48 [ 49.139117] RSP: 002b:00007ffd0e9021e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 49.139525] RAX: ffffffffffffffda RBX: 000055c02951ee50 RCX: 00007f53ae1261fd [ 49.139905] RDX: 0000000000000000 RSI: 000055bfff125478 RDI: 0000000000000010 [ 49.140282] RBP: 000055bfff125478 R08: 00007f53ae1f6b20 R09: 00007ffd0e902230 [ 49.140663] R10: 000055c029522000 R11: 0000000000000246 R12: 0000000000040000 [ 49.141040] R13: 000055c02951ef80 R14: 0000000000000000 R15: 000055c029521fc0 [ 49.141424] </TASK> [ 49.141552] Modules linked in: xe(+) drm_ttm_helper gpu_sched drm_suballoc_helper drm_gpuvm drm_exec drm_gpusvm i2c_algo_bit drm_buddy video wmi ttm drm_display_helper drm_kms_helper crct10dif_pclmul crc32_pclmul i2c_piix4 e1000 ghash_clmulni_intel i2c_smbus fuse [ 49.142824] CR2: ffffeb3ff1200000 [ 49.143010] ---[ end trace 0000000000000000 ]--- [ 49.143268] RIP: 0010:vmemmap_set_pmd+0xff/0x230 [ 49.143523] Code: 77 22 02 a9 ff ff 1f 00 74 58 48 8b 3d 62 77 22 02 48 85 ff 0f 85 9a 00 00 00 48 8d 7d 08 48 89 e9 31 c0 48 89 ea 48 83 e7 f8 <48> c7 45 00 00 00 00 00 48 29 f9 48 c7 45 48 00 00 00 00 83 c1 50 [ 49.144489] RSP: 0018:ffffc900016d37a8 EFLAGS: 00010282 [ 49.144775] RAX: 0000000000000000 RBX: ffff888164000000 RCX: ffffeb3ff1200000 [ 49.145154] RDX: ffffeb3ff1200000 RSI: 80000000000001e3 RDI: ffffeb3ff1200008 [ 49.145536] RBP: ffffeb3ff1200000 R08: ffffeb3ff1280000 R09: 0000000000000000 [ 49.145914] R10: ffff88817b94dc48 R11: 0000000000000003 R12: ffffeb3ff1280000 [ 49.146292] R13: 0000000000000000 R14: ffff88817b94dc48 R15: 8000000163e001e3 [ 49.146671] FS: 00007f53ae71d740(0000) GS:ffff88843fd80000(0000) knlGS:0000000000000000 [ 49.147097] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.147407] CR2: ffffeb3ff1200000 CR3: 000000017c7d2000 CR4: 0000000000750ef0 [ 49.147786] PKRU: 55555554 [ 49.147941] note: modprobe[302] exited with irqs disabled When a process leads the addition of a struct page to vmemmap (e.g. hot-plug), the page table update for the newly added vmemmap-based virtual address is updated first in init_mm's page table and then synchronized later. If the vmemmap-based virtual address is accessed through the process's page table before this sync, a page fault will occur. This translates vmemmap-based virtual address to direct-mapped virtual address and use it, if the current top-level page table is not init_mm's page table when accessing a vmemmap-based virtual address before this sync. Link: https://lkml.kernel.org/r/20250217114133.400063-2-gwan-gyeong.mun@intel.com Fixes: faf1c0008a33 ("x86/vmemmap: optimize for consecutive sections in partial populated PMDs") Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun(a)intel.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Hyeonggon Yoo <42.hyeyoo(a)gmail.com> Cc: Byungchul Park <byungchul(a)sk.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- arch/x86/mm/init_64.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) --- a/arch/x86/mm/init_64.c~x86-vmemmap-use-direct-mapped-va-instead-of-vmemmap-based-va +++ a/arch/x86/mm/init_64.c @@ -844,6 +844,17 @@ void __init paging_init(void) */ static unsigned long unused_pmd_start __meminitdata; +static void * __meminit vmemmap_va_to_kaddr(unsigned long vmemmap_va) +{ + void *kaddr = (void *)vmemmap_va; + pgd_t *pgd = __va(read_cr3_pa()); + + if (init_mm.pgd != pgd) + kaddr = __va(slow_virt_to_phys(kaddr)); + + return kaddr; +} + static void __meminit vmemmap_flush_unused_pmd(void) { if (!unused_pmd_start) @@ -851,7 +862,7 @@ static void __meminit vmemmap_flush_unus /* * Clears (unused_pmd_start, PMD_END] */ - memset((void *)unused_pmd_start, PAGE_UNUSED, + memset(vmemmap_va_to_kaddr(unused_pmd_start), PAGE_UNUSED, ALIGN(unused_pmd_start, PMD_SIZE) - unused_pmd_start); unused_pmd_start = 0; } @@ -882,7 +893,7 @@ static void __meminit __vmemmap_use_sub_ * case the first memmap never gets initialized e.g., because the memory * block never gets onlined). */ - memset((void *)start, 0, sizeof(struct page)); + memset(vmemmap_va_to_kaddr(start), 0, sizeof(struct page)); } static void __meminit vmemmap_use_sub_pmd(unsigned long start, unsigned long end) @@ -924,7 +935,7 @@ static void __meminit vmemmap_use_new_su * Mark with PAGE_UNUSED the unused parts of the new memmap range */ if (!IS_ALIGNED(start, PMD_SIZE)) - memset((void *)page, PAGE_UNUSED, start - page); + memset(vmemmap_va_to_kaddr(page), PAGE_UNUSED, start - page); /* * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of _ Patches currently in -mm which might be from gwan-gyeong.mun(a)intel.com are x86-vmemmap-use-direct-mapped-va-instead-of-vmemmap-based-va.patch

3 months

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[PATCH v4 4/4] ring-buffer: Use flush_kernel_vmap_range() over flush_dcache_folio()

by Steven Rostedt

From: Steven Rostedt <rostedt(a)goodmis.org> Some architectures do not have data cache coherency between user and kernel space. For these architectures, the cache needs to be flushed on both the kernel and user addresses so that user space can see the updates the kernel has made. Instead of using flush_dcache_folio() and playing with virt_to_folio() within the call to that function, use flush_kernel_vmap_range() which takes the virtual address and does the work for those architectures that need it. This also fixes a bug where the flush of the reader page only flushed one page. If the sub-buffer order is 1 or more, where the sub-buffer size would be greater than a page, it would miss the rest of the sub-buffer content, as the "reader page" is not just a page, but the size of a sub-buffer. Link: https://lore.kernel.org/all/CAG48ez3w0my4Rwttbc5tEbNsme6tc0mrSN95thjXUFaJ3a… Cc: stable(a)vger.kernel.org Fixes: 117c39200d9d7 ("ring-buffer: Introducing ring-buffer mapping functions"); Suggested-by: Jann Horn <jannh(a)google.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index d8d7b28e2c2f..c0f877d39a24 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6016,7 +6016,7 @@ static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer) meta->read = cpu_buffer->read; /* Some archs do not have data cache coherency between kernel and user-space */ - flush_dcache_folio(virt_to_folio(cpu_buffer->meta_page)); + flush_kernel_vmap_range(cpu_buffer->meta_page, PAGE_SIZE); } static void @@ -7319,7 +7319,8 @@ int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu) out: /* Some archs do not have data cache coherency between kernel and user-space */ - flush_dcache_folio(virt_to_folio(cpu_buffer->reader_page->page)); + flush_kernel_vmap_range(cpu_buffer->reader_page->page, + buffer->subbuf_size + BUF_PAGE_HDR_SIZE); rb_update_meta_page(cpu_buffer); -- 2.47.2

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[PATCH] HID: wacom: fix shift OOB in kfifo allocation for zero pktlen

by Qasim Ijaz

During wacom_parse_and_register() the code calls wacom_devm_kfifo_alloc to allocate a fifo. During this operation it passes kfifo_alloc a fifo_size of 0. Kfifo attempts to round the size passed to it to the next power of 2 via roundup_pow_of_two (queue-type data structures do this to maintain efficiency of operations). However during this phase a problem arises when the roundup_pow_of_two() function utilises a shift exponent of fls_long(n-1), where n is the fifo_size. Since n is 0 in this case and n is also an unsigned long, doing n-1 causes unsigned integer wrap-around to occur making the fifo_size 4294967295. So the code effectively does fls_long(4294967295) which results in 64. Returning back to roundup_pow_of_two(), the code utilises a shift exponent of 64. When a shift exponent of 64 is used on a 64-bit type such as 1UL it results in a shift-out-of-bounds. The root cause of the issue seems to stem from insufficient validation of wacom_compute_pktlen(), since in this case the fifo_size comes from wacom_wac->features.pktlen. During wacom_parse_and_register() the wacom_compute_pktlen() function sets the pktlen as 0. To fix this, we should handle cases where wacom_compute_pktlen() results in 0. Reported-by: syzbot <syzbot+d5204cbbdd921f1f7cad(a)syzkaller.appspotmail.com> Closes: https://syzkaller.appspot.com/bug?extid=d5204cbbdd921f1f7cad Tested-by: Qasim Ijaz <qasdev00(a)gmail.com> Cc: stable(a)vger.kernel.org Signed-off-by: Qasim Ijaz <qasdev00(a)gmail.com> --- drivers/hid/wacom_sys.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c index 97393a3083ca..9b2f3dbca467 100644 --- a/drivers/hid/wacom_sys.c +++ b/drivers/hid/wacom_sys.c @@ -2361,6 +2361,8 @@ static int wacom_parse_and_register(struct wacom *wacom, bool wireless) unsigned int connect_mask = HID_CONNECT_HIDRAW; features->pktlen = wacom_compute_pktlen(hdev); + if (!features->pktlen) + return -ENODEV; if (!devres_open_group(&hdev->dev, wacom, GFP_KERNEL)) return -ENOMEM; -- 2.39.5

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[PATCH] perf/x86/intel/uncore: Add error handling for uncore_msr_box_ctl()

by Wentao Liang

In mtl_uncore_msr_init_box(), the return value of uncore_msr_box_ctl() needs to be checked before being used as the parameter of wrmsrl(). A proper implementation can be found in ivbep_uncore_msr_init_box(). Add error handling for uncore_msr_box_ctl() to ensure the MSR write operation is only performed when a valid MSR address is returned. Fixes: c828441f21dd ("perf/x86/intel/uncore: Add Meteor Lake support") Cc: stable(a)vger.kernel.org # v6.3+ Signed-off-by: Wentao Liang <vulab(a)iscas.ac.cn> --- arch/x86/events/intel/uncore_snb.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/intel/uncore_snb.c b/arch/x86/events/intel/uncore_snb.c index 3934e1e4e3b1..84070388f495 100644 --- a/arch/x86/events/intel/uncore_snb.c +++ b/arch/x86/events/intel/uncore_snb.c @@ -691,7 +691,10 @@ static struct intel_uncore_type mtl_uncore_hac_cbox = { static void mtl_uncore_msr_init_box(struct intel_uncore_box *box) { - wrmsrl(uncore_msr_box_ctl(box), SNB_UNC_GLOBAL_CTL_EN); + unsigned int msr = uncore_msr_box_ctl(box); + + if (msr) + wrmsrl(msr, SNB_UNC_GLOBAL_CTL_EN); } static struct intel_uncore_ops mtl_uncore_msr_ops = { -- 2.42.0.windows.2

3 months

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