From c32537d49faba69f5c2146f1ab6dbacf26bff133 Mon Sep 17 00:00:00 2001 From: Markus Elfring Date: Sun, 7 May 2017 21:24:51 +0200 Subject: xtensa: Use seq_puts() in c_show() A string which did not contain a data format specification should be put into a sequence. Thus use the corresponding function "seq_puts". This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring Signed-off-by: Max Filippov --- arch/xtensa/kernel/setup.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/xtensa') diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c index 197e75b400b1..460a226699b4 100644 --- a/arch/xtensa/kernel/setup.c +++ b/arch/xtensa/kernel/setup.c @@ -594,8 +594,7 @@ c_show(struct seq_file *f, void *slot) (ccount_freq/10000) % 100, loops_per_jiffy/(500000/HZ), (loops_per_jiffy/(5000/HZ)) % 100); - - seq_printf(f,"flags\t\t: " + seq_puts(f, "flags\t\t: " #if XCHAL_HAVE_NMI "nmi " #endif -- cgit v1.2.3 From 5e78e465abcba4a21e5cc52bef41aa4b3361957d Mon Sep 17 00:00:00 2001 From: Markus Elfring Date: Thu, 25 Aug 2016 14:28:09 +0200 Subject: xtensa: ISS: Use kmalloc_array() in simdisk_init() * A multiplication for the size determination of a memory allocation indicated that an array data structure should be processed. Thus use the corresponding function "kmalloc_array". This issue was detected by using the Coccinelle software. * Replace the specification of a data type by a pointer dereference to make the corresponding size determination a bit safer according to the Linux coding style convention. Signed-off-by: Markus Elfring Signed-off-by: Max Filippov --- arch/xtensa/platforms/iss/simdisk.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/xtensa') diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c index 02e94bb3ad3e..c45b90bb9339 100644 --- a/arch/xtensa/platforms/iss/simdisk.c +++ b/arch/xtensa/platforms/iss/simdisk.c @@ -317,8 +317,7 @@ static int __init simdisk_init(void) if (simdisk_count > MAX_SIMDISK_COUNT) simdisk_count = MAX_SIMDISK_COUNT; - sddev = kmalloc(simdisk_count * sizeof(struct simdisk), - GFP_KERNEL); + sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL); if (sddev == NULL) goto out_unregister; -- cgit v1.2.3 From 6bf28969f617f0131e94deb5476f4c45f43fd847 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Mon, 5 Jun 2017 11:25:07 -0700 Subject: xtensa: reduce double exception literal reservation Double exception vector only needs 20 bytes of space for 5 literals, not 48. Reduce the reservation for double exception vector literals accordingly. This fixes build for configurations with small user exception vector size. Signed-off-by: Max Filippov --- arch/xtensa/kernel/vmlinux.lds.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/xtensa') diff --git a/arch/xtensa/kernel/vmlinux.lds.S b/arch/xtensa/kernel/vmlinux.lds.S index 30d9fc21e076..162c77e53ca8 100644 --- a/arch/xtensa/kernel/vmlinux.lds.S +++ b/arch/xtensa/kernel/vmlinux.lds.S @@ -118,7 +118,7 @@ SECTIONS SECTION_VECTOR (.KernelExceptionVector.text, KERNEL_VECTOR_VADDR) SECTION_VECTOR (.UserExceptionVector.literal, USER_VECTOR_VADDR - 4) SECTION_VECTOR (.UserExceptionVector.text, USER_VECTOR_VADDR) - SECTION_VECTOR (.DoubleExceptionVector.literal, DOUBLEEXC_VECTOR_VADDR - 48) + SECTION_VECTOR (.DoubleExceptionVector.literal, DOUBLEEXC_VECTOR_VADDR - 20) SECTION_VECTOR (.DoubleExceptionVector.text, DOUBLEEXC_VECTOR_VADDR) #endif @@ -306,13 +306,13 @@ SECTIONS .UserExceptionVector.literal) SECTION_VECTOR (_DoubleExceptionVector_literal, .DoubleExceptionVector.literal, - DOUBLEEXC_VECTOR_VADDR - 48, + DOUBLEEXC_VECTOR_VADDR - 20, SIZEOF(.UserExceptionVector.text), .UserExceptionVector.text) SECTION_VECTOR (_DoubleExceptionVector_text, .DoubleExceptionVector.text, DOUBLEEXC_VECTOR_VADDR, - 48, + 20, .DoubleExceptionVector.literal) . = (LOADADDR( .DoubleExceptionVector.text ) + SIZEOF( .DoubleExceptionVector.text ) + 3) & ~ 3; -- cgit v1.2.3 From e5c86679d5e864947a52fb31e45a425dea3e7fa9 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Mon, 5 Jun 2017 02:43:51 -0700 Subject: xtensa: don't use linux IRQ #0 Linux IRQ #0 is reserved for error reporting and may not be used. Increase NR_IRQS for one additional slot and increase irq_domain_add_legacy parameter first_irq value to 1, so that linux IRQ #0 is not associated with hardware IRQ #0 in legacy IRQ domains. Introduce macro XTENSA_PIC_LINUX_IRQ for static translation of xtensa PIC hardware IRQ # to linux IRQ #. Use this macro in XTFPGA platform data definitions. This fixes inability to use hardware IRQ #0 in configurations that don't use device tree and allows for non-identity mapping between linux IRQ # and hardware IRQ #. Cc: stable@vger.kernel.org Signed-off-by: Max Filippov --- arch/xtensa/include/asm/irq.h | 3 ++- arch/xtensa/kernel/irq.c | 5 ----- arch/xtensa/platforms/xtfpga/include/platform/hardware.h | 6 ++++-- arch/xtensa/platforms/xtfpga/setup.c | 10 +++++----- drivers/irqchip/irq-xtensa-mx.c | 2 +- drivers/irqchip/irq-xtensa-pic.c | 2 +- 6 files changed, 13 insertions(+), 15 deletions(-) (limited to 'arch/xtensa') diff --git a/arch/xtensa/include/asm/irq.h b/arch/xtensa/include/asm/irq.h index f71f88ea7646..19707db966f1 100644 --- a/arch/xtensa/include/asm/irq.h +++ b/arch/xtensa/include/asm/irq.h @@ -29,7 +29,8 @@ static inline void variant_irq_disable(unsigned int irq) { } # define PLATFORM_NR_IRQS 0 #endif #define XTENSA_NR_IRQS XCHAL_NUM_INTERRUPTS -#define NR_IRQS (XTENSA_NR_IRQS + VARIANT_NR_IRQS + PLATFORM_NR_IRQS) +#define NR_IRQS (XTENSA_NR_IRQS + VARIANT_NR_IRQS + PLATFORM_NR_IRQS + 1) +#define XTENSA_PIC_LINUX_IRQ(hwirq) ((hwirq) + 1) #if VARIANT_NR_IRQS == 0 static inline void variant_init_irq(void) { } diff --git a/arch/xtensa/kernel/irq.c b/arch/xtensa/kernel/irq.c index a265edd6ac37..99341028cc77 100644 --- a/arch/xtensa/kernel/irq.c +++ b/arch/xtensa/kernel/irq.c @@ -34,11 +34,6 @@ asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs) { int irq = irq_find_mapping(NULL, hwirq); - if (hwirq >= NR_IRQS) { - printk(KERN_EMERG "%s: cannot handle IRQ %d\n", - __func__, hwirq); - } - #ifdef CONFIG_DEBUG_STACKOVERFLOW /* Debugging check for stack overflow: is there less than 1KB free? */ { diff --git a/arch/xtensa/platforms/xtfpga/include/platform/hardware.h b/arch/xtensa/platforms/xtfpga/include/platform/hardware.h index dbeea2b440a1..1fda7e20dfcb 100644 --- a/arch/xtensa/platforms/xtfpga/include/platform/hardware.h +++ b/arch/xtensa/platforms/xtfpga/include/platform/hardware.h @@ -24,16 +24,18 @@ /* Interrupt configuration. */ -#define PLATFORM_NR_IRQS 10 +#define PLATFORM_NR_IRQS 0 /* Default assignment of LX60 devices to external interrupts. */ #ifdef CONFIG_XTENSA_MX #define DUART16552_INTNUM XCHAL_EXTINT3_NUM #define OETH_IRQ XCHAL_EXTINT4_NUM +#define C67X00_IRQ XCHAL_EXTINT8_NUM #else #define DUART16552_INTNUM XCHAL_EXTINT0_NUM #define OETH_IRQ XCHAL_EXTINT1_NUM +#define C67X00_IRQ XCHAL_EXTINT5_NUM #endif /* @@ -63,5 +65,5 @@ #define C67X00_PADDR (XCHAL_KIO_PADDR + 0x0D0D0000) #define C67X00_SIZE 0x10 -#define C67X00_IRQ 5 + #endif /* __XTENSA_XTAVNET_HARDWARE_H */ diff --git a/arch/xtensa/platforms/xtfpga/setup.c b/arch/xtensa/platforms/xtfpga/setup.c index 779be723eb2b..42285f35d313 100644 --- a/arch/xtensa/platforms/xtfpga/setup.c +++ b/arch/xtensa/platforms/xtfpga/setup.c @@ -175,8 +175,8 @@ static struct resource ethoc_res[] = { .flags = IORESOURCE_MEM, }, [2] = { /* IRQ number */ - .start = OETH_IRQ, - .end = OETH_IRQ, + .start = XTENSA_PIC_LINUX_IRQ(OETH_IRQ), + .end = XTENSA_PIC_LINUX_IRQ(OETH_IRQ), .flags = IORESOURCE_IRQ, }, }; @@ -213,8 +213,8 @@ static struct resource c67x00_res[] = { .flags = IORESOURCE_MEM, }, [1] = { /* IRQ number */ - .start = C67X00_IRQ, - .end = C67X00_IRQ, + .start = XTENSA_PIC_LINUX_IRQ(C67X00_IRQ), + .end = XTENSA_PIC_LINUX_IRQ(C67X00_IRQ), .flags = IORESOURCE_IRQ, }, }; @@ -247,7 +247,7 @@ static struct resource serial_resource = { static struct plat_serial8250_port serial_platform_data[] = { [0] = { .mapbase = DUART16552_PADDR, - .irq = DUART16552_INTNUM, + .irq = XTENSA_PIC_LINUX_IRQ(DUART16552_INTNUM), .flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_IOREMAP, .iotype = XCHAL_HAVE_BE ? UPIO_MEM32BE : UPIO_MEM32, diff --git a/drivers/irqchip/irq-xtensa-mx.c b/drivers/irqchip/irq-xtensa-mx.c index bb3ac5fe5846..72a391e01011 100644 --- a/drivers/irqchip/irq-xtensa-mx.c +++ b/drivers/irqchip/irq-xtensa-mx.c @@ -142,7 +142,7 @@ static struct irq_chip xtensa_mx_irq_chip = { int __init xtensa_mx_init_legacy(struct device_node *interrupt_parent) { struct irq_domain *root_domain = - irq_domain_add_legacy(NULL, NR_IRQS, 0, 0, + irq_domain_add_legacy(NULL, NR_IRQS - 1, 1, 0, &xtensa_mx_irq_domain_ops, &xtensa_mx_irq_chip); irq_set_default_host(root_domain); diff --git a/drivers/irqchip/irq-xtensa-pic.c b/drivers/irqchip/irq-xtensa-pic.c index 472ae1770964..f728755fa292 100644 --- a/drivers/irqchip/irq-xtensa-pic.c +++ b/drivers/irqchip/irq-xtensa-pic.c @@ -89,7 +89,7 @@ static struct irq_chip xtensa_irq_chip = { int __init xtensa_pic_init_legacy(struct device_node *interrupt_parent) { struct irq_domain *root_domain = - irq_domain_add_legacy(NULL, NR_IRQS, 0, 0, + irq_domain_add_legacy(NULL, NR_IRQS - 1, 1, 0, &xtensa_irq_domain_ops, &xtensa_irq_chip); irq_set_default_host(root_domain); return 0; -- cgit v1.2.3 From 1be7107fbe18eed3e319a6c3e83c78254b693acb Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 19 Jun 2017 04:03:24 -0700 Subject: mm: larger stack guard gap, between vmas Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov Original-patch-by: Michal Hocko Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Tested-by: Helge Deller # parisc Signed-off-by: Linus Torvalds --- Documentation/admin-guide/kernel-parameters.txt | 7 ++ arch/arc/mm/mmap.c | 2 +- arch/arm/mm/mmap.c | 4 +- arch/frv/mm/elf-fdpic.c | 2 +- arch/mips/mm/mmap.c | 2 +- arch/parisc/kernel/sys_parisc.c | 15 ++- arch/powerpc/mm/hugetlbpage-radix.c | 2 +- arch/powerpc/mm/mmap.c | 4 +- arch/powerpc/mm/slice.c | 2 +- arch/s390/mm/mmap.c | 4 +- arch/sh/mm/mmap.c | 4 +- arch/sparc/kernel/sys_sparc_64.c | 4 +- arch/sparc/mm/hugetlbpage.c | 2 +- arch/tile/mm/hugetlbpage.c | 2 +- arch/x86/kernel/sys_x86_64.c | 4 +- arch/x86/mm/hugetlbpage.c | 2 +- arch/xtensa/kernel/syscall.c | 2 +- fs/hugetlbfs/inode.c | 2 +- fs/proc/task_mmu.c | 4 - include/linux/mm.h | 53 ++++----- mm/gup.c | 5 - mm/memory.c | 38 ------ mm/mmap.c | 149 ++++++++++++++---------- 23 files changed, 152 insertions(+), 163 deletions(-) (limited to 'arch/xtensa') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0f5c3b4347c6..7737ab5d04b2 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3811,6 +3811,13 @@ expediting. Set to zero to disable automatic expediting. + stack_guard_gap= [MM] + override the default stack gap protection. The value + is in page units and it defines how many pages prior + to (for stacks growing down) resp. after (for stacks + growing up) the main stack are reserved for no other + mapping. Default value is 256 pages. + stacktrace [FTRACE] Enabled the stack tracer on boot up. diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c index 3e25e8d6486b..2e13683dfb24 100644 --- a/arch/arc/mm/mmap.c +++ b/arch/arc/mm/mmap.c @@ -65,7 +65,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 2239fde10b80..f0701d8d24df 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -90,7 +90,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } @@ -141,7 +141,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/arch/frv/mm/elf-fdpic.c b/arch/frv/mm/elf-fdpic.c index da82c25301e7..46aa289c5102 100644 --- a/arch/frv/mm/elf-fdpic.c +++ b/arch/frv/mm/elf-fdpic.c @@ -75,7 +75,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi addr = PAGE_ALIGN(addr); vma = find_vma(current->mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) goto success; } diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c index 64dd8bdd92c3..28adeabe851f 100644 --- a/arch/mips/mm/mmap.c +++ b/arch/mips/mm/mmap.c @@ -93,7 +93,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c index e5288638a1d9..378a754ca186 100644 --- a/arch/parisc/kernel/sys_parisc.c +++ b/arch/parisc/kernel/sys_parisc.c @@ -90,7 +90,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; - struct vm_area_struct *vma; + struct vm_area_struct *vma, *prev; unsigned long task_size = TASK_SIZE; int do_color_align, last_mmap; struct vm_unmapped_area_info info; @@ -117,9 +117,10 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, else addr = PAGE_ALIGN(addr); - vma = find_vma(mm, addr); + vma = find_vma_prev(mm, addr, &prev); if (task_size - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma)) && + (!prev || addr >= vm_end_gap(prev))) goto found_addr; } @@ -143,7 +144,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, const unsigned long len, const unsigned long pgoff, const unsigned long flags) { - struct vm_area_struct *vma; + struct vm_area_struct *vma, *prev; struct mm_struct *mm = current->mm; unsigned long addr = addr0; int do_color_align, last_mmap; @@ -177,9 +178,11 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, addr = COLOR_ALIGN(addr, last_mmap, pgoff); else addr = PAGE_ALIGN(addr); - vma = find_vma(mm, addr); + + vma = find_vma_prev(mm, addr, &prev); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma)) && + (!prev || addr >= vm_end_gap(prev))) goto found_addr; } diff --git a/arch/powerpc/mm/hugetlbpage-radix.c b/arch/powerpc/mm/hugetlbpage-radix.c index 6575b9aabef4..a12e86395025 100644 --- a/arch/powerpc/mm/hugetlbpage-radix.c +++ b/arch/powerpc/mm/hugetlbpage-radix.c @@ -68,7 +68,7 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, addr = ALIGN(addr, huge_page_size(h)); vma = find_vma(mm, addr); if (mm->task_size - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } /* diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c index 9dbd2a733d6b..0ee6be4f1ba4 100644 --- a/arch/powerpc/mm/mmap.c +++ b/arch/powerpc/mm/mmap.c @@ -112,7 +112,7 @@ radix__arch_get_unmapped_area(struct file *filp, unsigned long addr, addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (mm->task_size - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } @@ -157,7 +157,7 @@ radix__arch_get_unmapped_area_topdown(struct file *filp, addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (mm->task_size - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c index 966b9fccfa66..45f6740dd407 100644 --- a/arch/powerpc/mm/slice.c +++ b/arch/powerpc/mm/slice.c @@ -99,7 +99,7 @@ static int slice_area_is_free(struct mm_struct *mm, unsigned long addr, if ((mm->task_size - len) < addr) return 0; vma = find_vma(mm, addr); - return (!vma || (addr + len) <= vma->vm_start); + return (!vma || (addr + len) <= vm_start_gap(vma)); } static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice) diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index b017daed6887..b854b1da281a 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -101,7 +101,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) goto check_asce_limit; } @@ -151,7 +151,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) goto check_asce_limit; } diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c index 08e7af0be4a7..6a1a1297baae 100644 --- a/arch/sh/mm/mmap.c +++ b/arch/sh/mm/mmap.c @@ -64,7 +64,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } @@ -114,7 +114,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c index ef4520efc813..043544d0cda3 100644 --- a/arch/sparc/kernel/sys_sparc_64.c +++ b/arch/sparc/kernel/sys_sparc_64.c @@ -120,7 +120,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi vma = find_vma(mm, addr); if (task_size - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } @@ -183,7 +183,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, vma = find_vma(mm, addr); if (task_size - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c index 7c29d38e6b99..88855e383b34 100644 --- a/arch/sparc/mm/hugetlbpage.c +++ b/arch/sparc/mm/hugetlbpage.c @@ -120,7 +120,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, addr = ALIGN(addr, huge_page_size(h)); vma = find_vma(mm, addr); if (task_size - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } if (mm->get_unmapped_area == arch_get_unmapped_area) diff --git a/arch/tile/mm/hugetlbpage.c b/arch/tile/mm/hugetlbpage.c index cb10153b5c9f..03e5cc4e76e4 100644 --- a/arch/tile/mm/hugetlbpage.c +++ b/arch/tile/mm/hugetlbpage.c @@ -233,7 +233,7 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, addr = ALIGN(addr, huge_page_size(h)); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } if (current->mm->get_unmapped_area == arch_get_unmapped_area) diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index 207b8f2582c7..213ddf3e937d 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -144,7 +144,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (end - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } @@ -187,7 +187,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c index 302f43fd9c28..adad702b39cd 100644 --- a/arch/x86/mm/hugetlbpage.c +++ b/arch/x86/mm/hugetlbpage.c @@ -148,7 +148,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, addr = ALIGN(addr, huge_page_size(h)); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } if (mm->get_unmapped_area == arch_get_unmapped_area) diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c index 06937928cb72..74afbf02d07e 100644 --- a/arch/xtensa/kernel/syscall.c +++ b/arch/xtensa/kernel/syscall.c @@ -88,7 +88,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, /* At this point: (!vmm || addr < vmm->vm_end). */ if (TASK_SIZE - len < addr) return -ENOMEM; - if (!vmm || addr + len <= vmm->vm_start) + if (!vmm || addr + len <= vm_start_gap(vmm)) return addr; addr = vmm->vm_end; if (flags & MAP_SHARED) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index dde861387a40..d44f5456eb9b 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -200,7 +200,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, addr = ALIGN(addr, huge_page_size(h)); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index f0c8b33d99b1..520802da059c 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -300,11 +300,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid) /* We don't show the stack guard page in /proc/maps */ start = vma->vm_start; - if (stack_guard_page_start(vma, start)) - start += PAGE_SIZE; end = vma->vm_end; - if (stack_guard_page_end(vma, end)) - end -= PAGE_SIZE; seq_setwidth(m, 25 + sizeof(void *) * 6 - 1); seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ", diff --git a/include/linux/mm.h b/include/linux/mm.h index b892e95d4929..6f543a47fc92 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1393,12 +1393,6 @@ int clear_page_dirty_for_io(struct page *page); int get_cmdline(struct task_struct *task, char *buffer, int buflen); -/* Is the vma a continuation of the stack vma above it? */ -static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr) -{ - return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN); -} - static inline bool vma_is_anonymous(struct vm_area_struct *vma) { return !vma->vm_ops; @@ -1414,28 +1408,6 @@ bool vma_is_shmem(struct vm_area_struct *vma); static inline bool vma_is_shmem(struct vm_area_struct *vma) { return false; } #endif -static inline int stack_guard_page_start(struct vm_area_struct *vma, - unsigned long addr) -{ - return (vma->vm_flags & VM_GROWSDOWN) && - (vma->vm_start == addr) && - !vma_growsdown(vma->vm_prev, addr); -} - -/* Is the vma a continuation of the stack vma below it? */ -static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr) -{ - return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP); -} - -static inline int stack_guard_page_end(struct vm_area_struct *vma, - unsigned long addr) -{ - return (vma->vm_flags & VM_GROWSUP) && - (vma->vm_end == addr) && - !vma_growsup(vma->vm_next, addr); -} - int vma_is_stack_for_current(struct vm_area_struct *vma); extern unsigned long move_page_tables(struct vm_area_struct *vma, @@ -2222,6 +2194,7 @@ void page_cache_async_readahead(struct address_space *mapping, pgoff_t offset, unsigned long size); +extern unsigned long stack_guard_gap; /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */ extern int expand_stack(struct vm_area_struct *vma, unsigned long address); @@ -2250,6 +2223,30 @@ static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * m return vma; } +static inline unsigned long vm_start_gap(struct vm_area_struct *vma) +{ + unsigned long vm_start = vma->vm_start; + + if (vma->vm_flags & VM_GROWSDOWN) { + vm_start -= stack_guard_gap; + if (vm_start > vma->vm_start) + vm_start = 0; + } + return vm_start; +} + +static inline unsigned long vm_end_gap(struct vm_area_struct *vma) +{ + unsigned long vm_end = vma->vm_end; + + if (vma->vm_flags & VM_GROWSUP) { + vm_end += stack_guard_gap; + if (vm_end < vma->vm_end) + vm_end = -PAGE_SIZE; + } + return vm_end; +} + static inline unsigned long vma_pages(struct vm_area_struct *vma) { return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; diff --git a/mm/gup.c b/mm/gup.c index b3c7214d710d..576c4df58882 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -387,11 +387,6 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, /* mlock all present pages, but do not fault in new pages */ if ((*flags & (FOLL_POPULATE | FOLL_MLOCK)) == FOLL_MLOCK) return -ENOENT; - /* For mm_populate(), just skip the stack guard page. */ - if ((*flags & FOLL_POPULATE) && - (stack_guard_page_start(vma, address) || - stack_guard_page_end(vma, address + PAGE_SIZE))) - return -ENOENT; if (*flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; if (*flags & FOLL_REMOTE) diff --git a/mm/memory.c b/mm/memory.c index 2e65df1831d9..bb11c474857e 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2854,40 +2854,6 @@ out_release: return ret; } -/* - * This is like a special single-page "expand_{down|up}wards()", - * except we must first make sure that 'address{-|+}PAGE_SIZE' - * doesn't hit another vma. - */ -static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address) -{ - address &= PAGE_MASK; - if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) { - struct vm_area_struct *prev = vma->vm_prev; - - /* - * Is there a mapping abutting this one below? - * - * That's only ok if it's the same stack mapping - * that has gotten split.. - */ - if (prev && prev->vm_end == address) - return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM; - - return expand_downwards(vma, address - PAGE_SIZE); - } - if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) { - struct vm_area_struct *next = vma->vm_next; - - /* As VM_GROWSDOWN but s/below/above/ */ - if (next && next->vm_start == address + PAGE_SIZE) - return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM; - - return expand_upwards(vma, address + PAGE_SIZE); - } - return 0; -} - /* * We enter with non-exclusive mmap_sem (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. @@ -2904,10 +2870,6 @@ static int do_anonymous_page(struct vm_fault *vmf) if (vma->vm_flags & VM_SHARED) return VM_FAULT_SIGBUS; - /* Check if we need to add a guard page to the stack */ - if (check_stack_guard_page(vma, vmf->address) < 0) - return VM_FAULT_SIGSEGV; - /* * Use pte_alloc() instead of pte_alloc_map(). We can't run * pte_offset_map() on pmds where a huge pmd might be created diff --git a/mm/mmap.c b/mm/mmap.c index f82741e199c0..8e07976d5e47 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -183,6 +183,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) unsigned long retval; unsigned long newbrk, oldbrk; struct mm_struct *mm = current->mm; + struct vm_area_struct *next; unsigned long min_brk; bool populate; LIST_HEAD(uf); @@ -229,7 +230,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) } /* Check against existing mmap mappings. */ - if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) + next = find_vma(mm, oldbrk); + if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) goto out; /* Ok, looks good - let it rip. */ @@ -253,10 +255,22 @@ out: static long vma_compute_subtree_gap(struct vm_area_struct *vma) { - unsigned long max, subtree_gap; - max = vma->vm_start; - if (vma->vm_prev) - max -= vma->vm_prev->vm_end; + unsigned long max, prev_end, subtree_gap; + + /* + * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we + * allow two stack_guard_gaps between them here, and when choosing + * an unmapped area; whereas when expanding we only require one. + * That's a little inconsistent, but keeps the code here simpler. + */ + max = vm_start_gap(vma); + if (vma->vm_prev) { + prev_end = vm_end_gap(vma->vm_prev); + if (max > prev_end) + max -= prev_end; + else + max = 0; + } if (vma->vm_rb.rb_left) { subtree_gap = rb_entry(vma->vm_rb.rb_left, struct vm_area_struct, vm_rb)->rb_subtree_gap; @@ -352,7 +366,7 @@ static void validate_mm(struct mm_struct *mm) anon_vma_unlock_read(anon_vma); } - highest_address = vma->vm_end; + highest_address = vm_end_gap(vma); vma = vma->vm_next; i++; } @@ -541,7 +555,7 @@ void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, if (vma->vm_next) vma_gap_update(vma->vm_next); else - mm->highest_vm_end = vma->vm_end; + mm->highest_vm_end = vm_end_gap(vma); /* * vma->vm_prev wasn't known when we followed the rbtree to find the @@ -856,7 +870,7 @@ again: vma_gap_update(vma); if (end_changed) { if (!next) - mm->highest_vm_end = end; + mm->highest_vm_end = vm_end_gap(vma); else if (!adjust_next) vma_gap_update(next); } @@ -941,7 +955,7 @@ again: * mm->highest_vm_end doesn't need any update * in remove_next == 1 case. */ - VM_WARN_ON(mm->highest_vm_end != end); + VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma)); } } if (insert && file) @@ -1787,7 +1801,7 @@ unsigned long unmapped_area(struct vm_unmapped_area_info *info) while (true) { /* Visit left subtree if it looks promising */ - gap_end = vma->vm_start; + gap_end = vm_start_gap(vma); if (gap_end >= low_limit && vma->vm_rb.rb_left) { struct vm_area_struct *left = rb_entry(vma->vm_rb.rb_left, @@ -1798,7 +1812,7 @@ unsigned long unmapped_area(struct vm_unmapped_area_info *info) } } - gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; + gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0; check_current: /* Check if current node has a suitable gap */ if (gap_start > high_limit) @@ -1825,8 +1839,8 @@ check_current: vma = rb_entry(rb_parent(prev), struct vm_area_struct, vm_rb); if (prev == vma->vm_rb.rb_left) { - gap_start = vma->vm_prev->vm_end; - gap_end = vma->vm_start; + gap_start = vm_end_gap(vma->vm_prev); + gap_end = vm_start_gap(vma); goto check_current; } } @@ -1890,7 +1904,7 @@ unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) while (true) { /* Visit right subtree if it looks promising */ - gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; + gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0; if (gap_start <= high_limit && vma->vm_rb.rb_right) { struct vm_area_struct *right = rb_entry(vma->vm_rb.rb_right, @@ -1903,7 +1917,7 @@ unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) check_current: /* Check if current node has a suitable gap */ - gap_end = vma->vm_start; + gap_end = vm_start_gap(vma); if (gap_end < low_limit) return -ENOMEM; if (gap_start <= high_limit && gap_end - gap_start >= length) @@ -1929,7 +1943,7 @@ check_current: struct vm_area_struct, vm_rb); if (prev == vma->vm_rb.rb_right) { gap_start = vma->vm_prev ? - vma->vm_prev->vm_end : 0; + vm_end_gap(vma->vm_prev) : 0; goto check_current; } } @@ -1967,7 +1981,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; - struct vm_area_struct *vma; + struct vm_area_struct *vma, *prev; struct vm_unmapped_area_info info; if (len > TASK_SIZE - mmap_min_addr) @@ -1978,9 +1992,10 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, if (addr) { addr = PAGE_ALIGN(addr); - vma = find_vma(mm, addr); + vma = find_vma_prev(mm, addr, &prev); if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma)) && + (!prev || addr >= vm_end_gap(prev))) return addr; } @@ -2003,7 +2018,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, const unsigned long len, const unsigned long pgoff, const unsigned long flags) { - struct vm_area_struct *vma; + struct vm_area_struct *vma, *prev; struct mm_struct *mm = current->mm; unsigned long addr = addr0; struct vm_unmapped_area_info info; @@ -2018,9 +2033,10 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, /* requesting a specific address */ if (addr) { addr = PAGE_ALIGN(addr); - vma = find_vma(mm, addr); + vma = find_vma_prev(mm, addr, &prev); if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vma->vm_start)) + (!vma || addr + len <= vm_start_gap(vma)) && + (!prev || addr >= vm_end_gap(prev))) return addr; } @@ -2155,21 +2171,19 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr, * update accounting. This is shared with both the * grow-up and grow-down cases. */ -static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) +static int acct_stack_growth(struct vm_area_struct *vma, + unsigned long size, unsigned long grow) { struct mm_struct *mm = vma->vm_mm; struct rlimit *rlim = current->signal->rlim; - unsigned long new_start, actual_size; + unsigned long new_start; /* address space limit tests */ if (!may_expand_vm(mm, vma->vm_flags, grow)) return -ENOMEM; /* Stack limit test */ - actual_size = size; - if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN))) - actual_size -= PAGE_SIZE; - if (actual_size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur)) + if (size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur)) return -ENOMEM; /* mlock limit tests */ @@ -2207,17 +2221,30 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns int expand_upwards(struct vm_area_struct *vma, unsigned long address) { struct mm_struct *mm = vma->vm_mm; + struct vm_area_struct *next; + unsigned long gap_addr; int error = 0; if (!(vma->vm_flags & VM_GROWSUP)) return -EFAULT; /* Guard against wrapping around to address 0. */ - if (address < PAGE_ALIGN(address+4)) - address = PAGE_ALIGN(address+4); - else + address &= PAGE_MASK; + address += PAGE_SIZE; + if (!address) return -ENOMEM; + /* Enforce stack_guard_gap */ + gap_addr = address + stack_guard_gap; + if (gap_addr < address) + return -ENOMEM; + next = vma->vm_next; + if (next && next->vm_start < gap_addr) { + if (!(next->vm_flags & VM_GROWSUP)) + return -ENOMEM; + /* Check that both stack segments have the same anon_vma? */ + } + /* We must make sure the anon_vma is allocated. */ if (unlikely(anon_vma_prepare(vma))) return -ENOMEM; @@ -2261,7 +2288,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) if (vma->vm_next) vma_gap_update(vma->vm_next); else - mm->highest_vm_end = address; + mm->highest_vm_end = vm_end_gap(vma); spin_unlock(&mm->page_table_lock); perf_event_mmap(vma); @@ -2282,6 +2309,8 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) { struct mm_struct *mm = vma->vm_mm; + struct vm_area_struct *prev; + unsigned long gap_addr; int error; address &= PAGE_MASK; @@ -2289,6 +2318,17 @@ int expand_downwards(struct vm_area_struct *vma, if (error) return error; + /* Enforce stack_guard_gap */ + gap_addr = address - stack_guard_gap; + if (gap_addr > address) + return -ENOMEM; + prev = vma->vm_prev; + if (prev && prev->vm_end > gap_addr) { + if (!(prev->vm_flags & VM_GROWSDOWN)) + return -ENOMEM; + /* Check that both stack segments have the same anon_vma? */ + } + /* We must make sure the anon_vma is allocated. */ if (unlikely(anon_vma_prepare(vma))) return -ENOMEM; @@ -2343,28 +2383,25 @@ int expand_downwards(struct vm_area_struct *vma, return error; } -/* - * Note how expand_stack() refuses to expand the stack all the way to - * abut the next virtual mapping, *unless* that mapping itself is also - * a stack mapping. We want to leave room for a guard page, after all - * (the guard page itself is not added here, that is done by the - * actual page faulting logic) - * - * This matches the behavior of the guard page logic (see mm/memory.c: - * check_stack_guard_page()), which only allows the guard page to be - * removed under these circumstances. - */ +/* enforced gap between the expanding stack and other mappings. */ +unsigned long stack_guard_gap = 256UL<