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+ mm-gup-handle-null-pages-in-unpin_user_pages.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm/gup: handle NULL pages in unpin_user_pages() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-gup-handle-null-pages-in-unpin_user_pages.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: John Hubbard <jhubbard(a)nvidia.com> Subject: mm/gup: handle NULL pages in unpin_user_pages() Date: Wed, 20 Nov 2024 19:49:33 -0800 The recent addition of "pofs" (pages or folios) handling to gup has a flaw: it assumes that unpin_user_pages() handles NULL pages in the pages** array. That's not the case, as I discovered when I ran on a new configuration on my test machine. Fix this by skipping NULL pages in unpin_user_pages(), just like unpin_folios() already does. Details: when booting on x86 with "numa=fake=2 movablecore=4G" on Linux 6.12, and running this: tools/testing/selftests/mm/gup_longterm ...I get the following crash: BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:sanity_check_pinned_pages+0x3a/0x2d0 ... Call Trace: <TASK> ? __die_body+0x66/0xb0 ? page_fault_oops+0x30c/0x3b0 ? do_user_addr_fault+0x6c3/0x720 ? irqentry_enter+0x34/0x60 ? exc_page_fault+0x68/0x100 ? asm_exc_page_fault+0x22/0x30 ? sanity_check_pinned_pages+0x3a/0x2d0 unpin_user_pages+0x24/0xe0 check_and_migrate_movable_pages_or_folios+0x455/0x4b0 __gup_longterm_locked+0x3bf/0x820 ? mmap_read_lock_killable+0x12/0x50 ? __pfx_mmap_read_lock_killable+0x10/0x10 pin_user_pages+0x66/0xa0 gup_test_ioctl+0x358/0xb20 __se_sys_ioctl+0x6b/0xc0 do_syscall_64+0x7b/0x150 entry_SYSCALL_64_after_hwframe+0x76/0x7e Link: https://lkml.kernel.org/r/20241121034933.77502-1-jhubbard@nvidia.com Fixes: 94efde1d1539 ("mm/gup: avoid an unnecessary allocation call for FOLL_LONGTERM cases") Signed-off-by: John Hubbard <jhubbard(a)nvidia.com> Acked-by: David Hildenbrand <david(a)redhat.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Vivek Kasireddy <vivek.kasireddy(a)intel.com> Cc: Dave Airlie <airlied(a)redhat.com> Cc: Gerd Hoffmann <kraxel(a)redhat.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Christoph Hellwig <hch(a)infradead.org> Cc: Jason Gunthorpe <jgg(a)nvidia.com> Cc: Peter Xu <peterx(a)redhat.com> Cc: Arnd Bergmann <arnd(a)arndb.de> Cc: Daniel Vetter <daniel.vetter(a)ffwll.ch> Cc: Dongwon Kim <dongwon.kim(a)intel.com> Cc: Hugh Dickins <hughd(a)google.com> Cc: Junxiao Chang <junxiao.chang(a)intel.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/gup.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/mm/gup.c~mm-gup-handle-null-pages-in-unpin_user_pages +++ a/mm/gup.c @@ -52,7 +52,12 @@ static inline void sanity_check_pinned_p */ for (; npages; npages--, pages++) { struct page *page = *pages; - struct folio *folio = page_folio(page); + struct folio *folio; + + if (!page) + continue; + + folio = page_folio(page); if (is_zero_page(page) || !folio_test_anon(folio)) @@ -409,6 +414,10 @@ void unpin_user_pages(struct page **page sanity_check_pinned_pages(pages, npages); for (i = 0; i < npages; i += nr) { + if (!pages[i]) { + nr = 1; + continue; + } folio = gup_folio_next(pages, npages, i, &nr); gup_put_folio(folio, nr, FOLL_PIN); } _ Patches currently in -mm which might be from jhubbard(a)nvidia.com are mm-gup-handle-null-pages-in-unpin_user_pages.patch

2 months, 3 weeks

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+ fs-proc-kcorec-clear-ret-value-in-read_kcore_iter-after-successful-iov_iter_zero.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: fs/proc/kcore.c: clear ret value in read_kcore_iter after successful iov_iter_zero has been added to the -mm mm-hotfixes-unstable branch. Its filename is fs-proc-kcorec-clear-ret-value-in-read_kcore_iter-after-successful-iov_iter_zero.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: Jiri Olsa <jolsa(a)kernel.org> Subject: fs/proc/kcore.c: clear ret value in read_kcore_iter after successful iov_iter_zero Date: Fri, 22 Nov 2024 00:11:18 +0100 If iov_iter_zero succeeds after failed copy_from_kernel_nofault, we need to reset the ret value to zero otherwise it will be returned as final return value of read_kcore_iter. This fixes objdump -d dump over /proc/kcore for me. Link: https://lkml.kernel.org/r/20241121231118.3212000-1-jolsa@kernel.org Fixes: 3d5854d75e31 ("fs/proc/kcore.c: allow translation of physical memory addresses") Signed-off-by: Jiri Olsa <jolsa(a)kernel.org> Cc: Alexander Gordeev <agordeev(a)linux.ibm.com> Cc: Christian Brauner <brauner(a)kernel.org> Cc: <hca(a)linux.ibm.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/proc/kcore.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/proc/kcore.c~fs-proc-kcorec-clear-ret-value-in-read_kcore_iter-after-successful-iov_iter_zero +++ a/fs/proc/kcore.c @@ -600,6 +600,7 @@ static ssize_t read_kcore_iter(struct ki ret = -EFAULT; goto out; } + ret = 0; /* * We know the bounce buffer is safe to copy from, so * use _copy_to_iter() directly. _ Patches currently in -mm which might be from jolsa(a)kernel.org are fs-proc-kcorec-clear-ret-value-in-read_kcore_iter-after-successful-iov_iter_zero.patch

2 months, 3 weeks

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[PATCH v2] of: property: fw_devlink: Do not use interrupt-parent directly

by Samuel Holland

commit 7f00be96f125 ("of: property: Add device link support for interrupt-parent, dmas and -gpio(s)") started adding device links for the interrupt-parent property. commit 4104ca776ba3 ("of: property: Add fw_devlink support for interrupts") and commit f265f06af194 ("of: property: Fix fw_devlink handling of interrupts/interrupts-extended") later added full support for parsing the interrupts and interrupts-extended properties, which includes looking up the node of the parent domain. This made the handler for the interrupt-parent property redundant. In fact, creating device links based solely on interrupt-parent is problematic, because it can create spurious cycles. A node may have this property without itself being an interrupt controller or consumer. For example, this property is often present in the root node or a /soc bus node to set the default interrupt parent for child nodes. However, it is incorrect for the bus to depend on the interrupt controller, as some of the bus's children may not be interrupt consumers at all or may have a different interrupt parent. Resolving these spurious dependency cycles can cause an incorrect probe order for interrupt controller drivers. This was observed on a RISC-V system with both an APLIC and IMSIC under /soc, where interrupt-parent in /soc points to the APLIC, and the APLIC msi-parent points to the IMSIC. fw_devlink found three dependency cycles and attempted to probe the APLIC before the IMSIC. After applying this patch, there were no dependency cycles and the probe order was correct. Acked-by: Marc Zyngier <maz(a)kernel.org> Cc: stable(a)vger.kernel.org Fixes: 4104ca776ba3 ("of: property: Add fw_devlink support for interrupts") Signed-off-by: Samuel Holland <samuel.holland(a)sifive.com> --- Changes in v2: - Fix typo in commit message - Add Fixes: tag and CC stable drivers/of/property.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/of/property.c b/drivers/of/property.c index 11b922fde7af..7bd8390f2fba 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1213,7 +1213,6 @@ DEFINE_SIMPLE_PROP(iommus, "iommus", "#iommu-cells") DEFINE_SIMPLE_PROP(mboxes, "mboxes", "#mbox-cells") DEFINE_SIMPLE_PROP(io_channels, "io-channels", "#io-channel-cells") DEFINE_SIMPLE_PROP(io_backends, "io-backends", "#io-backend-cells") -DEFINE_SIMPLE_PROP(interrupt_parent, "interrupt-parent", NULL) DEFINE_SIMPLE_PROP(dmas, "dmas", "#dma-cells") DEFINE_SIMPLE_PROP(power_domains, "power-domains", "#power-domain-cells") DEFINE_SIMPLE_PROP(hwlocks, "hwlocks", "#hwlock-cells") @@ -1359,7 +1358,6 @@ static const struct supplier_bindings of_supplier_bindings[] = { { .parse_prop = parse_mboxes, }, { .parse_prop = parse_io_channels, }, { .parse_prop = parse_io_backends, }, - { .parse_prop = parse_interrupt_parent, }, { .parse_prop = parse_dmas, .optional = true, }, { .parse_prop = parse_power_domains, }, { .parse_prop = parse_hwlocks, }, -- 2.45.1

2 months, 3 weeks

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[PATCH v2] iommu/arm-smmu: Defer probe of clients after smmu device bound

by Pratyush Brahma

Null pointer dereference occurs due to a race between smmu driver probe and client driver probe, when of_dma_configure() for client is called after the iommu_device_register() for smmu driver probe has executed but before the driver_bound() for smmu driver has been called. Following is how the race occurs: T1:Smmu device probe T2: Client device probe really_probe() arm_smmu_device_probe() iommu_device_register() really_probe() platform_dma_configure() of_dma_configure() of_dma_configure_id() of_iommu_configure() iommu_probe_device() iommu_init_device() arm_smmu_probe_device() arm_smmu_get_by_fwnode() driver_find_device_by_fwnode() driver_find_device() next_device() klist_next() /* null ptr assigned to smmu */ /* null ptr dereference while smmu->streamid_mask */ driver_bound() klist_add_tail() When this null smmu pointer is dereferenced later in arm_smmu_probe_device, the device crashes. Fix this by deferring the probe of the client device until the smmu device has bound to the arm smmu driver. Fixes: 021bb8420d44 ("iommu/arm-smmu: Wire up generic configuration support") Cc: stable(a)vger.kernel.org Co-developed-by: Prakash Gupta <quic_guptap(a)quicinc.com> Signed-off-by: Prakash Gupta <quic_guptap(a)quicinc.com> Signed-off-by: Pratyush Brahma <quic_pbrahma(a)quicinc.com> --- Changes in v2: Fix kernel test robot warning Add stable kernel list in cc Link to v1: https://lore.kernel.org/all/20241001055633.21062-1-quic_pbrahma@quicinc.com/ drivers/iommu/arm/arm-smmu/arm-smmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index 723273440c21..7c778b7eb8c8 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1437,6 +1437,9 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) goto out_free; } else { smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode); + if (!smmu) + return ERR_PTR(dev_err_probe(dev, -EPROBE_DEFER, + "smmu dev has not bound yet\n")); } ret = -EINVAL; -- 2.17.1

2 months, 3 weeks

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linux-stable-rc.git: queue/6.12 VS. linux-6.12.y

by Sedat Dilek

Hi Greg and Sasha, Can you please check the queue/6.12 Git branch? Looks like it includes queue/6.11 material. Thanks. Best regards, -Sedat-

2 months, 3 weeks

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FAILED: patch "[PATCH] x86/stackprotector: Work around strict Clang TLS symbol" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 577c134d311b9b94598d7a0c86be1f431f823003 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111735-paging-quintet-7ce1@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 577c134d311b9b94598d7a0c86be1f431f823003 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel <ardb(a)kernel.org> Date: Tue, 5 Nov 2024 10:57:46 -0500 Subject: [PATCH] x86/stackprotector: Work around strict Clang TLS symbol requirements GCC and Clang both implement stack protector support based on Thread Local Storage (TLS) variables, and this is used in the kernel to implement per-task stack cookies, by copying a task's stack cookie into a per-CPU variable every time it is scheduled in. Both now also implement -mstack-protector-guard-symbol=, which permits the TLS variable to be specified directly. This is useful because it will allow to move away from using a fixed offset of 40 bytes into the per-CPU area on x86_64, which requires a lot of special handling in the per-CPU code and the runtime relocation code. However, while GCC is rather lax in its implementation of this command line option, Clang actually requires that the provided symbol name refers to a TLS variable (i.e., one declared with __thread), although it also permits the variable to be undeclared entirely, in which case it will use an implicit declaration of the right type. The upshot of this is that Clang will emit the correct references to the stack cookie variable in most cases, e.g., 10d: 64 a1 00 00 00 00 mov %fs:0x0,%eax 10f: R_386_32 __stack_chk_guard However, if a non-TLS definition of the symbol in question is visible in the same compilation unit (which amounts to the whole of vmlinux if LTO is enabled), it will drop the per-CPU prefix and emit a load from a bogus address. Work around this by using a symbol name that never occurs in C code, and emit it as an alias in the linker script. Fixes: 3fb0fdb3bbe7 ("x86/stackprotector/32: Make the canary into a regular percpu variable") Signed-off-by: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Brian Gerst <brgerst(a)gmail.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Nathan Chancellor <nathan(a)kernel.org> Tested-by: Nathan Chancellor <nathan(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/1854 Link: https://lore.kernel.org/r/20241105155801.1779119-2-brgerst@gmail.com diff --git a/arch/x86/Makefile b/arch/x86/Makefile index cd75e78a06c1..5b773b34768d 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -142,9 +142,10 @@ ifeq ($(CONFIG_X86_32),y) ifeq ($(CONFIG_STACKPROTECTOR),y) ifeq ($(CONFIG_SMP),y) - KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard + KBUILD_CFLAGS += -mstack-protector-guard-reg=fs \ + -mstack-protector-guard-symbol=__ref_stack_chk_guard else - KBUILD_CFLAGS += -mstack-protector-guard=global + KBUILD_CFLAGS += -mstack-protector-guard=global endif endif else diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S index 324686bca368..b7ea3e8e9ecc 100644 --- a/arch/x86/entry/entry.S +++ b/arch/x86/entry/entry.S @@ -51,3 +51,19 @@ EXPORT_SYMBOL_GPL(mds_verw_sel); .popsection THUNK warn_thunk_thunk, __warn_thunk + +#ifndef CONFIG_X86_64 +/* + * Clang's implementation of TLS stack cookies requires the variable in + * question to be a TLS variable. If the variable happens to be defined as an + * ordinary variable with external linkage in the same compilation unit (which + * amounts to the whole of vmlinux with LTO enabled), Clang will drop the + * segment register prefix from the references, resulting in broken code. Work + * around this by avoiding the symbol used in -mstack-protector-guard-symbol= + * entirely in the C code, and use an alias emitted by the linker script + * instead. + */ +#ifdef CONFIG_STACKPROTECTOR +EXPORT_SYMBOL(__ref_stack_chk_guard); +#endif +#endif diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h index 25466c4d2134..3674006e3974 100644 --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -20,3 +20,6 @@ extern void cmpxchg8b_emu(void); #endif +#if defined(__GENKSYMS__) && defined(CONFIG_STACKPROTECTOR) +extern unsigned long __ref_stack_chk_guard; +#endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a5f221ea5688..f43bb974fc66 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2089,8 +2089,10 @@ void syscall_init(void) #ifdef CONFIG_STACKPROTECTOR DEFINE_PER_CPU(unsigned long, __stack_chk_guard); +#ifndef CONFIG_SMP EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); #endif +#endif #endif /* CONFIG_X86_64 */ diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index b8c5741d2fb4..feb8102a9ca7 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -491,6 +491,9 @@ SECTIONS . = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), "kernel image bigger than KERNEL_IMAGE_SIZE"); +/* needed for Clang - see arch/x86/entry/entry.S */ +PROVIDE(__ref_stack_chk_guard = __stack_chk_guard); + #ifdef CONFIG_X86_64 /* * Per-cpu symbols which need to be offset from __per_cpu_load

2 months, 3 weeks

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FAILED: patch "[PATCH] x86/stackprotector: Work around strict Clang TLS symbol" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 577c134d311b9b94598d7a0c86be1f431f823003 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111739-dimmed-aspirate-171d@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 577c134d311b9b94598d7a0c86be1f431f823003 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel <ardb(a)kernel.org> Date: Tue, 5 Nov 2024 10:57:46 -0500 Subject: [PATCH] x86/stackprotector: Work around strict Clang TLS symbol requirements GCC and Clang both implement stack protector support based on Thread Local Storage (TLS) variables, and this is used in the kernel to implement per-task stack cookies, by copying a task's stack cookie into a per-CPU variable every time it is scheduled in. Both now also implement -mstack-protector-guard-symbol=, which permits the TLS variable to be specified directly. This is useful because it will allow to move away from using a fixed offset of 40 bytes into the per-CPU area on x86_64, which requires a lot of special handling in the per-CPU code and the runtime relocation code. However, while GCC is rather lax in its implementation of this command line option, Clang actually requires that the provided symbol name refers to a TLS variable (i.e., one declared with __thread), although it also permits the variable to be undeclared entirely, in which case it will use an implicit declaration of the right type. The upshot of this is that Clang will emit the correct references to the stack cookie variable in most cases, e.g., 10d: 64 a1 00 00 00 00 mov %fs:0x0,%eax 10f: R_386_32 __stack_chk_guard However, if a non-TLS definition of the symbol in question is visible in the same compilation unit (which amounts to the whole of vmlinux if LTO is enabled), it will drop the per-CPU prefix and emit a load from a bogus address. Work around this by using a symbol name that never occurs in C code, and emit it as an alias in the linker script. Fixes: 3fb0fdb3bbe7 ("x86/stackprotector/32: Make the canary into a regular percpu variable") Signed-off-by: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Brian Gerst <brgerst(a)gmail.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Nathan Chancellor <nathan(a)kernel.org> Tested-by: Nathan Chancellor <nathan(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/1854 Link: https://lore.kernel.org/r/20241105155801.1779119-2-brgerst@gmail.com diff --git a/arch/x86/Makefile b/arch/x86/Makefile index cd75e78a06c1..5b773b34768d 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -142,9 +142,10 @@ ifeq ($(CONFIG_X86_32),y) ifeq ($(CONFIG_STACKPROTECTOR),y) ifeq ($(CONFIG_SMP),y) - KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard + KBUILD_CFLAGS += -mstack-protector-guard-reg=fs \ + -mstack-protector-guard-symbol=__ref_stack_chk_guard else - KBUILD_CFLAGS += -mstack-protector-guard=global + KBUILD_CFLAGS += -mstack-protector-guard=global endif endif else diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S index 324686bca368..b7ea3e8e9ecc 100644 --- a/arch/x86/entry/entry.S +++ b/arch/x86/entry/entry.S @@ -51,3 +51,19 @@ EXPORT_SYMBOL_GPL(mds_verw_sel); .popsection THUNK warn_thunk_thunk, __warn_thunk + +#ifndef CONFIG_X86_64 +/* + * Clang's implementation of TLS stack cookies requires the variable in + * question to be a TLS variable. If the variable happens to be defined as an + * ordinary variable with external linkage in the same compilation unit (which + * amounts to the whole of vmlinux with LTO enabled), Clang will drop the + * segment register prefix from the references, resulting in broken code. Work + * around this by avoiding the symbol used in -mstack-protector-guard-symbol= + * entirely in the C code, and use an alias emitted by the linker script + * instead. + */ +#ifdef CONFIG_STACKPROTECTOR +EXPORT_SYMBOL(__ref_stack_chk_guard); +#endif +#endif diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h index 25466c4d2134..3674006e3974 100644 --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -20,3 +20,6 @@ extern void cmpxchg8b_emu(void); #endif +#if defined(__GENKSYMS__) && defined(CONFIG_STACKPROTECTOR) +extern unsigned long __ref_stack_chk_guard; +#endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a5f221ea5688..f43bb974fc66 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2089,8 +2089,10 @@ void syscall_init(void) #ifdef CONFIG_STACKPROTECTOR DEFINE_PER_CPU(unsigned long, __stack_chk_guard); +#ifndef CONFIG_SMP EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); #endif +#endif #endif /* CONFIG_X86_64 */ diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index b8c5741d2fb4..feb8102a9ca7 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -491,6 +491,9 @@ SECTIONS . = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), "kernel image bigger than KERNEL_IMAGE_SIZE"); +/* needed for Clang - see arch/x86/entry/entry.S */ +PROVIDE(__ref_stack_chk_guard = __stack_chk_guard); + #ifdef CONFIG_X86_64 /* * Per-cpu symbols which need to be offset from __per_cpu_load

2 months, 3 weeks

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FAILED: patch "[PATCH] x86/stackprotector: Work around strict Clang TLS symbol" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 577c134d311b9b94598d7a0c86be1f431f823003 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111736-handshake-thesaurus-43e6@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 577c134d311b9b94598d7a0c86be1f431f823003 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel <ardb(a)kernel.org> Date: Tue, 5 Nov 2024 10:57:46 -0500 Subject: [PATCH] x86/stackprotector: Work around strict Clang TLS symbol requirements GCC and Clang both implement stack protector support based on Thread Local Storage (TLS) variables, and this is used in the kernel to implement per-task stack cookies, by copying a task's stack cookie into a per-CPU variable every time it is scheduled in. Both now also implement -mstack-protector-guard-symbol=, which permits the TLS variable to be specified directly. This is useful because it will allow to move away from using a fixed offset of 40 bytes into the per-CPU area on x86_64, which requires a lot of special handling in the per-CPU code and the runtime relocation code. However, while GCC is rather lax in its implementation of this command line option, Clang actually requires that the provided symbol name refers to a TLS variable (i.e., one declared with __thread), although it also permits the variable to be undeclared entirely, in which case it will use an implicit declaration of the right type. The upshot of this is that Clang will emit the correct references to the stack cookie variable in most cases, e.g., 10d: 64 a1 00 00 00 00 mov %fs:0x0,%eax 10f: R_386_32 __stack_chk_guard However, if a non-TLS definition of the symbol in question is visible in the same compilation unit (which amounts to the whole of vmlinux if LTO is enabled), it will drop the per-CPU prefix and emit a load from a bogus address. Work around this by using a symbol name that never occurs in C code, and emit it as an alias in the linker script. Fixes: 3fb0fdb3bbe7 ("x86/stackprotector/32: Make the canary into a regular percpu variable") Signed-off-by: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Brian Gerst <brgerst(a)gmail.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Nathan Chancellor <nathan(a)kernel.org> Tested-by: Nathan Chancellor <nathan(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/1854 Link: https://lore.kernel.org/r/20241105155801.1779119-2-brgerst@gmail.com diff --git a/arch/x86/Makefile b/arch/x86/Makefile index cd75e78a06c1..5b773b34768d 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -142,9 +142,10 @@ ifeq ($(CONFIG_X86_32),y) ifeq ($(CONFIG_STACKPROTECTOR),y) ifeq ($(CONFIG_SMP),y) - KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard + KBUILD_CFLAGS += -mstack-protector-guard-reg=fs \ + -mstack-protector-guard-symbol=__ref_stack_chk_guard else - KBUILD_CFLAGS += -mstack-protector-guard=global + KBUILD_CFLAGS += -mstack-protector-guard=global endif endif else diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S index 324686bca368..b7ea3e8e9ecc 100644 --- a/arch/x86/entry/entry.S +++ b/arch/x86/entry/entry.S @@ -51,3 +51,19 @@ EXPORT_SYMBOL_GPL(mds_verw_sel); .popsection THUNK warn_thunk_thunk, __warn_thunk + +#ifndef CONFIG_X86_64 +/* + * Clang's implementation of TLS stack cookies requires the variable in + * question to be a TLS variable. If the variable happens to be defined as an + * ordinary variable with external linkage in the same compilation unit (which + * amounts to the whole of vmlinux with LTO enabled), Clang will drop the + * segment register prefix from the references, resulting in broken code. Work + * around this by avoiding the symbol used in -mstack-protector-guard-symbol= + * entirely in the C code, and use an alias emitted by the linker script + * instead. + */ +#ifdef CONFIG_STACKPROTECTOR +EXPORT_SYMBOL(__ref_stack_chk_guard); +#endif +#endif diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h index 25466c4d2134..3674006e3974 100644 --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -20,3 +20,6 @@ extern void cmpxchg8b_emu(void); #endif +#if defined(__GENKSYMS__) && defined(CONFIG_STACKPROTECTOR) +extern unsigned long __ref_stack_chk_guard; +#endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a5f221ea5688..f43bb974fc66 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2089,8 +2089,10 @@ void syscall_init(void) #ifdef CONFIG_STACKPROTECTOR DEFINE_PER_CPU(unsigned long, __stack_chk_guard); +#ifndef CONFIG_SMP EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); #endif +#endif #endif /* CONFIG_X86_64 */ diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index b8c5741d2fb4..feb8102a9ca7 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -491,6 +491,9 @@ SECTIONS . = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), "kernel image bigger than KERNEL_IMAGE_SIZE"); +/* needed for Clang - see arch/x86/entry/entry.S */ +PROVIDE(__ref_stack_chk_guard = __stack_chk_guard); + #ifdef CONFIG_X86_64 /* * Per-cpu symbols which need to be offset from __per_cpu_load

2 months, 3 weeks

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FAILED: patch "[PATCH] x86/stackprotector: Work around strict Clang TLS symbol" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 577c134d311b9b94598d7a0c86be1f431f823003 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111737-undead-acutely-d4b1@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 577c134d311b9b94598d7a0c86be1f431f823003 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel <ardb(a)kernel.org> Date: Tue, 5 Nov 2024 10:57:46 -0500 Subject: [PATCH] x86/stackprotector: Work around strict Clang TLS symbol requirements GCC and Clang both implement stack protector support based on Thread Local Storage (TLS) variables, and this is used in the kernel to implement per-task stack cookies, by copying a task's stack cookie into a per-CPU variable every time it is scheduled in. Both now also implement -mstack-protector-guard-symbol=, which permits the TLS variable to be specified directly. This is useful because it will allow to move away from using a fixed offset of 40 bytes into the per-CPU area on x86_64, which requires a lot of special handling in the per-CPU code and the runtime relocation code. However, while GCC is rather lax in its implementation of this command line option, Clang actually requires that the provided symbol name refers to a TLS variable (i.e., one declared with __thread), although it also permits the variable to be undeclared entirely, in which case it will use an implicit declaration of the right type. The upshot of this is that Clang will emit the correct references to the stack cookie variable in most cases, e.g., 10d: 64 a1 00 00 00 00 mov %fs:0x0,%eax 10f: R_386_32 __stack_chk_guard However, if a non-TLS definition of the symbol in question is visible in the same compilation unit (which amounts to the whole of vmlinux if LTO is enabled), it will drop the per-CPU prefix and emit a load from a bogus address. Work around this by using a symbol name that never occurs in C code, and emit it as an alias in the linker script. Fixes: 3fb0fdb3bbe7 ("x86/stackprotector/32: Make the canary into a regular percpu variable") Signed-off-by: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Brian Gerst <brgerst(a)gmail.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Nathan Chancellor <nathan(a)kernel.org> Tested-by: Nathan Chancellor <nathan(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/1854 Link: https://lore.kernel.org/r/20241105155801.1779119-2-brgerst@gmail.com diff --git a/arch/x86/Makefile b/arch/x86/Makefile index cd75e78a06c1..5b773b34768d 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -142,9 +142,10 @@ ifeq ($(CONFIG_X86_32),y) ifeq ($(CONFIG_STACKPROTECTOR),y) ifeq ($(CONFIG_SMP),y) - KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard + KBUILD_CFLAGS += -mstack-protector-guard-reg=fs \ + -mstack-protector-guard-symbol=__ref_stack_chk_guard else - KBUILD_CFLAGS += -mstack-protector-guard=global + KBUILD_CFLAGS += -mstack-protector-guard=global endif endif else diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S index 324686bca368..b7ea3e8e9ecc 100644 --- a/arch/x86/entry/entry.S +++ b/arch/x86/entry/entry.S @@ -51,3 +51,19 @@ EXPORT_SYMBOL_GPL(mds_verw_sel); .popsection THUNK warn_thunk_thunk, __warn_thunk + +#ifndef CONFIG_X86_64 +/* + * Clang's implementation of TLS stack cookies requires the variable in + * question to be a TLS variable. If the variable happens to be defined as an + * ordinary variable with external linkage in the same compilation unit (which + * amounts to the whole of vmlinux with LTO enabled), Clang will drop the + * segment register prefix from the references, resulting in broken code. Work + * around this by avoiding the symbol used in -mstack-protector-guard-symbol= + * entirely in the C code, and use an alias emitted by the linker script + * instead. + */ +#ifdef CONFIG_STACKPROTECTOR +EXPORT_SYMBOL(__ref_stack_chk_guard); +#endif +#endif diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h index 25466c4d2134..3674006e3974 100644 --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -20,3 +20,6 @@ extern void cmpxchg8b_emu(void); #endif +#if defined(__GENKSYMS__) && defined(CONFIG_STACKPROTECTOR) +extern unsigned long __ref_stack_chk_guard; +#endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a5f221ea5688..f43bb974fc66 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2089,8 +2089,10 @@ void syscall_init(void) #ifdef CONFIG_STACKPROTECTOR DEFINE_PER_CPU(unsigned long, __stack_chk_guard); +#ifndef CONFIG_SMP EXPORT_PER_CPU_SYMBOL(__stack_chk_guard); #endif +#endif #endif /* CONFIG_X86_64 */ diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index b8c5741d2fb4..feb8102a9ca7 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -491,6 +491,9 @@ SECTIONS . = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), "kernel image bigger than KERNEL_IMAGE_SIZE"); +/* needed for Clang - see arch/x86/entry/entry.S */ +PROVIDE(__ref_stack_chk_guard = __stack_chk_guard); + #ifdef CONFIG_X86_64 /* * Per-cpu symbols which need to be offset from __per_cpu_load

2 months, 3 weeks

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[PATCH] mm/huge_memory: Fix to make vma_adjust_trans_huge() use find_vma() correctly

by Jeongjun Park

vma_adjust_trans_huge() uses find_vma() to get the VMA, but find_vma() uses the returned pointer without any verification, even though it may return NULL. In this case, NULL pointer dereference may occur, so to prevent this, vma_adjust_trans_huge() should be fix to verify the return value of find_vma(). Cc: <stable(a)vger.kernel.org> Fixes: 685405020b9f ("mm/khugepaged: stop using vma linked list") Signed-off-by: Jeongjun Park <aha310510(a)gmail.com> --- mm/huge_memory.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 5734d5d5060f..db55b8abae2e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2941,9 +2941,12 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma, */ if (adjust_next > 0) { struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end); - unsigned long nstart = next->vm_start; - nstart += adjust_next; - split_huge_pmd_if_needed(next, nstart); + + if (likely(next)) { + unsigned long nstart = next->vm_start; + nstart += adjust_next; + split_huge_pmd_if_needed(next, nstart); + } } } --

2 months, 3 weeks

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