January 2023 - Linux-stable-mirror

[PATCH] comedi: adv_pci1760: Fix PWM instruction handling

by Ian Abbott

(Actually, this is fixing the "Read the Current Status" command sent to the device's outgoing mailbox, but it is only currently used for the PWM instructions.) The PCI-1760 is operated mostly by sending commands to a set of Outgoing Mailbox registers, waiting for the command to complete, and reading the result from the Incoming Mailbox registers. One of these commands is the "Read the Current Status" command. The number of this command is 0x07 (see the User's Manual for the PCI-1760 at <https://advdownload.advantech.com/productfile/Downloadfile2/1-11P6653/PCI-1…>. The `PCI1760_CMD_GET_STATUS` macro defined in the driver should expand to this command number 0x07, but unfortunately it currently expands to 0x03. (Command number 0x03 is not defined in the User's Manual.) Correct the definition of the `PCI1760_CMD_GET_STATUS` macro to fix it. This is used by all the PWM subdevice related instructions handled by `pci1760_pwm_insn_config()` which are probably all broken. The effect of sending the undefined command number 0x03 is not known. Fixes: 14b93bb6bbf0 ("staging: comedi: adv_pci_dio: separate out PCI-1760 support") Cc: <stable(a)vger.kernel.org> # v4.5+ Signed-off-by: Ian Abbott <abbotti(a)mev.co.uk> --- drivers/comedi/drivers/adv_pci1760.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/comedi/drivers/adv_pci1760.c b/drivers/comedi/drivers/adv_pci1760.c index fcfc2e299110..27f3890f471d 100644 --- a/drivers/comedi/drivers/adv_pci1760.c +++ b/drivers/comedi/drivers/adv_pci1760.c @@ -58,7 +58,7 @@ #define PCI1760_CMD_CLR_IMB2 0x00 /* Clears IMB2 */ #define PCI1760_CMD_SET_DO 0x01 /* Set output state */ #define PCI1760_CMD_GET_DO 0x02 /* Read output status */ -#define PCI1760_CMD_GET_STATUS 0x03 /* Read current status */ +#define PCI1760_CMD_GET_STATUS 0x07 /* Read current status */ #define PCI1760_CMD_GET_FW_VER 0x0e /* Read firmware version */ #define PCI1760_CMD_GET_HW_VER 0x0f /* Read hardware version */ #define PCI1760_CMD_SET_PWM_HI(x) (0x10 + (x) * 2) /* Set "hi" period */ -- 2.35.1

1 year, 5 months

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[PATCH v2 stable 4.19 1/2] mm/khugepaged: fix GUP-fast interaction by sending IPI

by Jann Horn

Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to ensure that the page table was not removed by khugepaged in between. However, lockless_pages_from_mm() still requires that the page table is not concurrently freed. Fix it by sending IPIs (if the architecture uses semi-RCU-style page table freeing) before freeing/reusing page tables. Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com Fixes: ba76149f47d8 ("thp: khugepaged") Signed-off-by: Jann Horn <jannh(a)google.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: John Hubbard <jhubbard(a)nvidia.com> Cc: Peter Xu <peterx(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> [manual backport: two of the three places in khugepaged that can free ptes were refactored into a common helper between 5.15 and 6.0; TLB flushing was refactored between 5.4 and 5.10; TLB flushing was refactored between 4.19 and 5.4; pmd collapse for PTE-mapped THP was only added in 5.4; ugly hack needed in <=4.19 for s390] Signed-off-by: Jann Horn <jannh(a)google.com> --- added an incredibly ugly hack to work around the s390 issue reported in https://lore.kernel.org/all/Y5aaQqNH71IMVks0@sashalap/ include/asm-generic/tlb.h | 6 ++++++ mm/khugepaged.c | 15 +++++++++++++++ mm/memory.c | 5 +++++ 3 files changed, 26 insertions(+) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index db72ad39853b..737f5cb0dc84 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -61,6 +61,12 @@ struct mmu_table_batch { extern void tlb_table_flush(struct mmu_gather *tlb); extern void tlb_remove_table(struct mmu_gather *tlb, void *table); +void tlb_remove_table_sync_one(void); + +#else + +static inline void tlb_remove_table_sync_one(void) { } + #endif /* diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 5dd14ef2e1de..0f217bb9b534 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -23,6 +23,19 @@ #include <asm/pgalloc.h> #include "internal.h" +/* gross hack for <=4.19 stable */ +#ifdef CONFIG_S390 +static void tlb_remove_table_smp_sync(void *arg) +{ + /* Simply deliver the interrupt */ +} + +static void tlb_remove_table_sync_one(void) +{ + smp_call_function(tlb_remove_table_smp_sync, NULL, 1); +} +#endif + enum scan_result { SCAN_FAIL, SCAN_SUCCEED, @@ -1045,6 +1058,7 @@ static void collapse_huge_page(struct mm_struct *mm, _pmd = pmdp_collapse_flush(vma, address, pmd); spin_unlock(pmd_ptl); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); + tlb_remove_table_sync_one(); spin_lock(pte_ptl); isolated = __collapse_huge_page_isolate(vma, address, pte); @@ -1294,6 +1308,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) _pmd = pmdp_collapse_flush(vma, addr, pmd); spin_unlock(ptl); mm_dec_nr_ptes(mm); + tlb_remove_table_sync_one(); pte_free(mm, pmd_pgtable(_pmd)); } up_write(&mm->mmap_sem); diff --git a/mm/memory.c b/mm/memory.c index 800834cff4e6..b80ce6b3c8f4 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -362,6 +362,11 @@ static void tlb_remove_table_smp_sync(void *arg) /* Simply deliver the interrupt */ } +void tlb_remove_table_sync_one(void) +{ + smp_call_function(tlb_remove_table_smp_sync, NULL, 1); +} + static void tlb_remove_table_one(void *table) { /* base-commit: c1ccef20f08e192228a2056808113b453d18c094 -- 2.39.0.rc1.256.g54fd8350bd-goog

1 year, 5 months

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[PATCH] VMCI: Use threaded irqs instead of tasklets

by vdasa＠vmware.com

From: Vishnu Dasa <vdasa(a)vmware.com> The vmci_dispatch_dgs() tasklet function calls vmci_read_data() which uses wait_event() resulting in invalid sleep in an atomic context (and therefore potentially in a deadlock). Use threaded irqs to fix this issue and completely remove usage of tasklets. [ 20.264639] BUG: sleeping function called from invalid context at drivers/misc/vmw_vmci/vmci_guest.c:145 [ 20.264643] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 762, name: vmtoolsd [ 20.264645] preempt_count: 101, expected: 0 [ 20.264646] RCU nest depth: 0, expected: 0 [ 20.264647] 1 lock held by vmtoolsd/762: [ 20.264648] #0: ffff0000874ae440 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_connect+0x60/0x330 [vsock] [ 20.264658] Preemption disabled at: [ 20.264659] [<ffff80000151d7d8>] vmci_send_datagram+0x44/0xa0 [vmw_vmci] [ 20.264665] CPU: 0 PID: 762 Comm: vmtoolsd Not tainted 5.19.0-0.rc8.20220727git39c3c396f813.60.fc37.aarch64 #1 [ 20.264667] Hardware name: VMware, Inc. VBSA/VBSA, BIOS VEFI 12/31/2020 [ 20.264668] Call trace: [ 20.264669] dump_backtrace+0xc4/0x130 [ 20.264672] show_stack+0x24/0x80 [ 20.264673] dump_stack_lvl+0x88/0xb4 [ 20.264676] dump_stack+0x18/0x34 [ 20.264677] __might_resched+0x1a0/0x280 [ 20.264679] __might_sleep+0x58/0x90 [ 20.264681] vmci_read_data+0x74/0x120 [vmw_vmci] [ 20.264683] vmci_dispatch_dgs+0x64/0x204 [vmw_vmci] [ 20.264686] tasklet_action_common.constprop.0+0x13c/0x150 [ 20.264688] tasklet_action+0x40/0x50 [ 20.264689] __do_softirq+0x23c/0x6b4 [ 20.264690] __irq_exit_rcu+0x104/0x214 [ 20.264691] irq_exit_rcu+0x1c/0x50 [ 20.264693] el1_interrupt+0x38/0x6c [ 20.264695] el1h_64_irq_handler+0x18/0x24 [ 20.264696] el1h_64_irq+0x68/0x6c [ 20.264697] preempt_count_sub+0xa4/0xe0 [ 20.264698] _raw_spin_unlock_irqrestore+0x64/0xb0 [ 20.264701] vmci_send_datagram+0x7c/0xa0 [vmw_vmci] [ 20.264703] vmci_datagram_dispatch+0x84/0x100 [vmw_vmci] [ 20.264706] vmci_datagram_send+0x2c/0x40 [vmw_vmci] [ 20.264709] vmci_transport_send_control_pkt+0xb8/0x120 [vmw_vsock_vmci_transport] [ 20.264711] vmci_transport_connect+0x40/0x7c [vmw_vsock_vmci_transport] [ 20.264713] vsock_connect+0x278/0x330 [vsock] [ 20.264715] __sys_connect_file+0x8c/0xc0 [ 20.264718] __sys_connect+0x84/0xb4 [ 20.264720] __arm64_sys_connect+0x2c/0x3c [ 20.264721] invoke_syscall+0x78/0x100 [ 20.264723] el0_svc_common.constprop.0+0x68/0x124 [ 20.264724] do_el0_svc+0x38/0x4c [ 20.264725] el0_svc+0x60/0x180 [ 20.264726] el0t_64_sync_handler+0x11c/0x150 [ 20.264728] el0t_64_sync+0x190/0x194 Signed-off-by: Vishnu Dasa <vdasa(a)vmware.com> Suggested-by: Zack Rusin <zackr(a)vmware.com> Reported-by: Nadav Amit <namit(a)vmware.com> Reported-by: Nathan Chancellor <nathan(a)kernel.org> Tested-by: Nathan Chancellor <nathan(a)kernel.org> Fixes: 463713eb6164 ("VMCI: dma dg: add support for DMA datagrams receive") Cc: <stable(a)vger.kernel.org> # v5.18+ Cc: VMware PV-Drivers Reviewers <pv-drivers(a)vmware.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Bryan Tan <bryantan(a)vmware.com> --- drivers/misc/vmw_vmci/vmci_guest.c | 49 ++++++++++++------------------ 1 file changed, 19 insertions(+), 30 deletions(-) diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c index aa7b05de97dd..6ab717b4a5db 100644 --- a/drivers/misc/vmw_vmci/vmci_guest.c +++ b/drivers/misc/vmw_vmci/vmci_guest.c @@ -56,8 +56,6 @@ struct vmci_guest_device { bool exclusive_vectors; - struct tasklet_struct datagram_tasklet; - struct tasklet_struct bm_tasklet; struct wait_queue_head inout_wq; void *data_buffer; @@ -304,9 +302,8 @@ static int vmci_check_host_caps(struct pci_dev *pdev) * This function assumes that it has exclusive access to the data * in register(s) for the duration of the call. */ -static void vmci_dispatch_dgs(unsigned long data) +static void vmci_dispatch_dgs(struct vmci_guest_device *vmci_dev) { - struct vmci_guest_device *vmci_dev = (struct vmci_guest_device *)data; u8 *dg_in_buffer = vmci_dev->data_buffer; struct vmci_datagram *dg; size_t dg_in_buffer_size = VMCI_MAX_DG_SIZE; @@ -465,10 +462,8 @@ static void vmci_dispatch_dgs(unsigned long data) * Scans the notification bitmap for raised flags, clears them * and handles the notifications. */ -static void vmci_process_bitmap(unsigned long data) +static void vmci_process_bitmap(struct vmci_guest_device *dev) { - struct vmci_guest_device *dev = (struct vmci_guest_device *)data; - if (!dev->notification_bitmap) { dev_dbg(dev->dev, "No bitmap present in %s\n", __func__); return; @@ -486,13 +481,13 @@ static irqreturn_t vmci_interrupt(int irq, void *_dev) struct vmci_guest_device *dev = _dev; /* - * If we are using MSI-X with exclusive vectors then we simply schedule - * the datagram tasklet, since we know the interrupt was meant for us. + * If we are using MSI-X with exclusive vectors then we simply call + * vmci_dispatch_dgs(), since we know the interrupt was meant for us. * Otherwise we must read the ICR to determine what to do. */ if (dev->exclusive_vectors) { - tasklet_schedule(&dev->datagram_tasklet); + vmci_dispatch_dgs(dev); } else { unsigned int icr; @@ -502,12 +497,12 @@ static irqreturn_t vmci_interrupt(int irq, void *_dev) return IRQ_NONE; if (icr & VMCI_ICR_DATAGRAM) { - tasklet_schedule(&dev->datagram_tasklet); + vmci_dispatch_dgs(dev); icr &= ~VMCI_ICR_DATAGRAM; } if (icr & VMCI_ICR_NOTIFICATION) { - tasklet_schedule(&dev->bm_tasklet); + vmci_process_bitmap(dev); icr &= ~VMCI_ICR_NOTIFICATION; } @@ -536,7 +531,7 @@ static irqreturn_t vmci_interrupt_bm(int irq, void *_dev) struct vmci_guest_device *dev = _dev; /* For MSI-X we can just assume it was meant for us. */ - tasklet_schedule(&dev->bm_tasklet); + vmci_process_bitmap(dev); return IRQ_HANDLED; } @@ -638,10 +633,6 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, vmci_dev->iobase = iobase; vmci_dev->mmio_base = mmio_base; - tasklet_init(&vmci_dev->datagram_tasklet, - vmci_dispatch_dgs, (unsigned long)vmci_dev); - tasklet_init(&vmci_dev->bm_tasklet, - vmci_process_bitmap, (unsigned long)vmci_dev); init_waitqueue_head(&vmci_dev->inout_wq); if (mmio_base != NULL) { @@ -808,8 +799,9 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, * Request IRQ for legacy or MSI interrupts, or for first * MSI-X vector. */ - error = request_irq(pci_irq_vector(pdev, 0), vmci_interrupt, - IRQF_SHARED, KBUILD_MODNAME, vmci_dev); + error = request_threaded_irq(pci_irq_vector(pdev, 0), NULL, + vmci_interrupt, IRQF_SHARED, + KBUILD_MODNAME, vmci_dev); if (error) { dev_err(&pdev->dev, "Irq %u in use: %d\n", pci_irq_vector(pdev, 0), error); @@ -823,9 +815,9 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, * between the vectors. */ if (vmci_dev->exclusive_vectors) { - error = request_irq(pci_irq_vector(pdev, 1), - vmci_interrupt_bm, 0, KBUILD_MODNAME, - vmci_dev); + error = request_threaded_irq(pci_irq_vector(pdev, 1), NULL, + vmci_interrupt_bm, 0, + KBUILD_MODNAME, vmci_dev); if (error) { dev_err(&pdev->dev, "Failed to allocate irq %u: %d\n", @@ -833,9 +825,11 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, goto err_free_irq; } if (caps_in_use & VMCI_CAPS_DMA_DATAGRAM) { - error = request_irq(pci_irq_vector(pdev, 2), - vmci_interrupt_dma_datagram, - 0, KBUILD_MODNAME, vmci_dev); + error = request_threaded_irq(pci_irq_vector(pdev, 2), + NULL, + vmci_interrupt_dma_datagram, + 0, KBUILD_MODNAME, + vmci_dev); if (error) { dev_err(&pdev->dev, "Failed to allocate irq %u: %d\n", @@ -871,8 +865,6 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, err_free_irq: free_irq(pci_irq_vector(pdev, 0), vmci_dev); - tasklet_kill(&vmci_dev->datagram_tasklet); - tasklet_kill(&vmci_dev->bm_tasklet); err_disable_msi: pci_free_irq_vectors(pdev); @@ -943,9 +935,6 @@ static void vmci_guest_remove_device(struct pci_dev *pdev) free_irq(pci_irq_vector(pdev, 0), vmci_dev); pci_free_irq_vectors(pdev); - tasklet_kill(&vmci_dev->datagram_tasklet); - tasklet_kill(&vmci_dev->bm_tasklet); - if (vmci_dev->notification_bitmap) { /* * The device reset above cleared the bitmap state of the -- 2.34.1

1 year, 5 months

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[PATCH] x86/kexec: fix double vfree of image->elf_headers

by Vlastimil Babka

An investigation of a "Trying to vfree() nonexistent vm area" bug occurring in arch_kimage_file_post_load_cleanup() doing a vfree(image->elf_headers) in our 5.14-based kernel yielded the following double vfree() scenario, also present in mainline: SYSCALL_DEFINE5(kexec_file_load) kimage_file_alloc_init() kimage_file_prepare_segments() arch_kexec_kernel_image_probe() kexec_image_load_default() kexec_bzImage64_ops.load() bzImage64_load() crash_load_segments() prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz); image->elf_headers = kbuf.buffer; ret = kexec_add_buffer(&kbuf); if (ret) vfree((void *)image->elf_headers); // first vfree() if (ret) kimage_file_post_load_cleanup() vfree(image->elf_headers); // second vfree() AFAICS the scenario is possible since v5.19 commit b3e34a47f989 ("x86/kexec: fix memory leak of elf header buffer") that was marked for stable and also was backported to our kernel. Fix the problem by setting the pointer to NULL after the first vfree(). Also set elf_headers_sz to 0, as kimage_file_post_load_cleanup() does. Fixes: b3e34a47f989 ("x86/kexec: fix memory leak of elf header buffer") Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz> Cc: Baoquan He <bhe(a)redhat.com> Cc: Dave Young <dyoung(a)redhat.com> Cc: <stable(a)vger.kernel.org> --- arch/x86/kernel/crash.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index 9730c88530fc..0d651c05a49e 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -403,6 +403,8 @@ int crash_load_segments(struct kimage *image) ret = kexec_add_buffer(&kbuf); if (ret) { vfree((void *)image->elf_headers); + image->elf_headers = NULL; + image->elf_headers_sz = 0; return ret; } image->elf_load_addr = kbuf.mem; -- 2.39.0

1 year, 5 months

2
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[PATCH v2 1/3] KVM: arm64: Fix S1PTW handling on RO memslots

by Marc Zyngier

A recent development on the EFI front has resulted in guests having their page tables baked in the firmware binary, and mapped into the IPA space as part of a read-only memslot. Not only is this legitimate, but it also results in added security, so thumbs up. It is possible to take an S1PTW translation fault if the S1 PTs are unmapped at stage-2. However, KVM unconditionally treats S1PTW as a write to correctly handle hardware AF/DB updates to the S1 PTs. Furthermore, KVM injects an exception into the guest for S1PTW writes. In the aforementioned case this results in the guest taking an abort it won't recover from, as the S1 PTs mapping the vectors suffer from the same problem. So clearly our handling is... wrong. Instead, switch to a two-pronged approach: - On S1PTW translation fault, handle the fault as a read - On S1PTW permission fault, handle the fault as a write This is of no consequence to SW that *writes* to its PTs (the write will trigger a non-S1PTW fault), and SW that uses RO PTs will not use HW-assisted AF/DB anyway, as that'd be wrong. Only in the case described in c4ad98e4b72c ("KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch") do we end-up with two back-to-back faults (page being evicted and faulted back). I don't think this is a case worth optimising for. Fixes: c4ad98e4b72c ("KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch") Reviewed-by: Oliver Upton <oliver.upton(a)linux.dev> Reviewed-by: Ard Biesheuvel <ardb(a)kernel.org> Regression-tested-by: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Marc Zyngier <maz(a)kernel.org> Cc: stable(a)vger.kernel.org --- arch/arm64/include/asm/kvm_emulate.h | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 9bdba47f7e14..0d40c48d8132 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -373,8 +373,26 @@ static __always_inline int kvm_vcpu_sys_get_rt(struct kvm_vcpu *vcpu) static inline bool kvm_is_write_fault(struct kvm_vcpu *vcpu) { - if (kvm_vcpu_abt_iss1tw(vcpu)) - return true; + if (kvm_vcpu_abt_iss1tw(vcpu)) { + /* + * Only a permission fault on a S1PTW should be + * considered as a write. Otherwise, page tables baked + * in a read-only memslot will result in an exception + * being delivered in the guest. + * + * The drawback is that we end-up faulting twice if the + * guest is using any of HW AF/DB: a translation fault + * to map the page containing the PT (read only at + * first), then a permission fault to allow the flags + * to be set. + */ + switch (kvm_vcpu_trap_get_fault_type(vcpu)) { + case ESR_ELx_FSC_PERM: + return true; + default: + return false; + } + } if (kvm_vcpu_trap_is_iabt(vcpu)) return false; -- 2.34.1

1 year, 5 months

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[PATCH] docs: gdbmacros: print newest record

by John Ogness

@head_id points to the newest record, but the printing loop exits when it increments to this value (before printing). Exit the printing loop after the newest record has been printed. The python-based function in scripts/gdb/linux/dmesg.py already does this correctly. Fixes: e60768311af8 ("scripts/gdb: update for lockless printk ringbuffer") Cc: stable(a)vger.kernel.org Signed-off-by: John Ogness <john.ogness(a)linutronix.de> --- Documentation/admin-guide/kdump/gdbmacros.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kdump/gdbmacros.txt b/Documentation/admin-guide/kdump/gdbmacros.txt index 82aecdcae8a6..030de95e3e6b 100644 --- a/Documentation/admin-guide/kdump/gdbmacros.txt +++ b/Documentation/admin-guide/kdump/gdbmacros.txt @@ -312,10 +312,10 @@ define dmesg set var $prev_flags = $info->flags end - set var $id = ($id + 1) & $id_mask if ($id == $end_id) loop_break end + set var $id = ($id + 1) & $id_mask end end document dmesg base-commit: 1b929c02afd37871d5afb9d498426f83432e71c2 -- 2.30.2

1 year, 5 months

2
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[PATCH 1/1] serial: pch_uart: Pass correct sg to dma_unmap_sg()

by Ilpo Järvinen

A local variable sg is used to store scatterlist pointer in pch_dma_tx_complete(). The for loop doing Tx byte accounting before dma_unmap_sg() alters sg in its increment statement. Therefore, the pointer passed into dma_unmap_sg() won't match to the one given to dma_map_sg(). To fix the problem, use priv->sg_tx_p directly in dma_unmap_sg() instead of the local variable. Fixes: da3564ee027e ("pch_uart: add multi-scatter processing") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> --- drivers/tty/serial/pch_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 3d54a43768cd..9576ba8bbc40 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -749,7 +749,7 @@ static void pch_dma_tx_complete(void *arg) uart_xmit_advance(port, sg_dma_len(sg)); async_tx_ack(priv->desc_tx); - dma_unmap_sg(port->dev, sg, priv->orig_nent, DMA_TO_DEVICE); + dma_unmap_sg(port->dev, priv->sg_tx_p, priv->orig_nent, DMA_TO_DEVICE); priv->tx_dma_use = 0; priv->nent = 0; priv->orig_nent = 0; -- 2.30.2

1 year, 5 months

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Re: [PATCH v6] media: uvcvideo: Fix race condition with usb_kill_urb

by Ricardo Ribalda

Hi Hillf Thanks for the heads up On Tue, 3 Jan 2023 at 03:25, Hillf Danton <hdanton(a)sina.com> wrote: > > On 02 Jan 2023 15:48:01 +0100 Ricardo Ribalda <ribalda(a)chromium.org> > > --- a/drivers/media/usb/uvc/uvc_ctrl.c > > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > > @@ -1442,6 +1442,9 @@ static void uvc_ctrl_status_event_work(struct work_struct *work) > > > > uvc_ctrl_status_event(w->chain, w->ctrl, w->data); > > > > + if (dev->flush_status) > > + return; > > + > > /* Resubmit the URB. */ > > w->urb->interval = dev->int_ep->desc.bInterval; > > ret = usb_submit_urb(w->urb, GFP_KERNEL); > > diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c > > index 7518ffce22ed..e457889345a3 100644 > > --- a/drivers/media/usb/uvc/uvc_status.c > > +++ b/drivers/media/usb/uvc/uvc_status.c > > @@ -6,6 +6,7 @@ > > * Laurent Pinchart (laurent.pinchart(a)ideasonboard.com) > > */ > > > > +#include <asm/barrier.h> > > #include <linux/kernel.h> > > #include <linux/input.h> > > #include <linux/slab.h> > > @@ -309,5 +310,44 @@ int uvc_status_start(struct uvc_device *dev, gfp_t flags) > > > > void uvc_status_stop(struct uvc_device *dev) > > { > > + struct uvc_ctrl_work *w = &dev->async_ctrl; > > + > > + /* Prevent the asynchronous control handler from requeing the URB */ > > + dev->flush_status = true; > > + > > + /* > > + * The barrier is needed so the flush_status change is visible to other > > + * CPUs running the asynchronous handler before usb_kill_urb() is > > + * called below. > > + */ > > + smp_mb(); > > Given unpaired mb, take a look at the release/acquire memory barrier pairing > in c5b2cbdbdac5 ("ipc/mqueue.c: update/document memory barriers") Would it work? to replace: dev->flush_status = true; smp_mb(); with: smp_store_release(&dev->flush_status, 1); and then read it always with: smp_load_acquire(&dev->flush_status); Thanks! > > > + > > + /* If there is any status event on the queue, process it. */ > > + if (cancel_work_sync(&w->work)) > > + uvc_ctrl_status_event(w->chain, w->ctrl, w->data); > > + > > + /* Kill the urb. */ > > usb_kill_urb(dev->int_urb); > > + > > + /* > > + * The URB completion handler may have queued asynchronous work. This > > + * won't resubmit the URB as flush_status is set, but it needs to be > > + * cancelled before returning or it could then race with a future > > + * uvc_status_start() call. > > + */ > > + if (cancel_work_sync(&w->work)) > > + uvc_ctrl_status_event(w->chain, w->ctrl, w->data); > > + > > + /* > > + * From this point, there are no events on the queue and the status URB > > + * is dead, this is, no events will be queued until uvc_status_start() > > + * is called. > > + */ > > + dev->flush_status = false; > > + > > + /* > > + * Write to memory the value of flush_status before uvc_status_start() > > + * is called again. > > + */ > > + smp_mb(); > > } -- Ricardo Ribalda

1 year, 5 months

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5.15-stable io_uring backport

by Jens Axboe

Hi Greg, Here's the series we discussed before the break, no changes since then. Last 3 patches are new stable backports, the rest is backporting the 5.15.85 io_uring codebase to 5.10-stable. This is done to make 5.10 maintainable wrt io_uring, and importantly, to bring back the native io workers to 5.10-stable. -- Jens Axboe

1 year, 5 months

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lening

by INFO

-- Goede dag, Wij zijn gespecialiseerd in het verstrekken van leningen voor bedrijven, projecten, zakelijke en persoonlijke leningen tegen een rentepercentage van 2% per jaar. Wij bieden: - * Investeringen in projectleningen * Investeringen in zakelijke leningen * Persoonlijke Lening Investeringen Neem contact met ons op voor meer details. Ondergetekende, Online reclamebureau.

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