On Fri, 26 Jul 2019 at 07:12, Daniel Axtens <dja@xxxxxxxxxx> wrote:
>
> >> It appears that stack overflows are *not* detected when KASAN_VMALLOC
> >> and VMAP_STACK are enabled.
> >>
> >> Tested with:
> >> insmod drivers/misc/lkdtm/lkdtm.ko cpoint_name=DIRECT cpoint_type=EXHAUST_STACK
> >>
> >> I've also attached the .config. Anything I missed?
> >>
>
> So this is a pretty fun bug.
>
> From qemu it seems that CPU#0 is stuck in
> queued_spin_lock_slowpath. Some registers contain the address of
> logbuf_lock. Looking at a stack in crash, we're printing:
>
> crash> bt -S 0xffffc90000530000 695
> PID: 695 TASK: ffff888069933b00 CPU: 0 COMMAND: "modprobe"
> #0 [ffffc90000530000] __schedule at ffffffff834832e5
> #1 [ffffc900005300d0] vscnprintf at ffffffff83464398
> #2 [ffffc900005300f8] vprintk_store at ffffffff8123d9f0
> #3 [ffffc90000530160] vprintk_emit at ffffffff8123e2f9
> #4 [ffffc900005301b0] vprintk_func at ffffffff8123ff06
> #5 [ffffc900005301c8] printk at ffffffff8123efb0
> #6 [ffffc90000530278] recursive_loop at ffffffffc0459939 [lkdtm]
> #7 [ffffc90000530708] recursive_loop at ffffffffc045994a [lkdtm]
> #8 [ffffc90000530b98] recursive_loop at ffffffffc045994a [lkdtm]
> ...
>
> We seem to be deadlocking on logbuf_lock because we take the stack
> overflow inside printk after it takes the lock, as recursive_loop
> attempts to print its status. Then we try to printk() some information
> about the double-fault, which tries to take the lock again, and blam,
> we're deadlocked.
>
> I didn't see it in my build because I happen to just access the stack
> differently with lock debugging on - we happen to overflow the stack
> while not holding the lock.
>
> So I think this is a generic bug, not related to KASAN_VMALLOC. IIUC,
> it's not safe to kill stack-overflowing tasks with die() because they
> could be holding arbitrary locks. Instead we should panic() the box.
> (panic prints without taking locks.)
>
> The following patch works for me, does it fix things for you?
>
> -----------------------------------------------------
>
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index 4bb0f8447112..bfb0ec667c09 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -301,13 +301,14 @@ __visible void __noreturn handle_stack_overflow(const char *message,
> struct pt_regs *regs,
> unsigned long fault_address)
> {
> - printk(KERN_EMERG "BUG: stack guard page was hit at %p (stack is %p..%p)\n",
> - (void *)fault_address, current->stack,
> - (char *)current->stack + THREAD_SIZE - 1);
> - die(message, regs, 0);
> + /*
> + * It's not safe to kill the task, as it's in kernel space and
> + * might be holding important locks. Just panic.
> + */
>
> - /* Be absolutely certain we don't return. */
> - panic("%s", message);
> + panic("%s - stack guard page was hit at %p (stack is %p..%p)",
> + message, (void *)fault_address, current->stack,
> + (char *)current->stack + THREAD_SIZE - 1);
> }
>
>
> -----------------------------------------------------
Many thanks for debugging this! Indeed, this seems to fix things for me.
Best Wishes,
-- Marco
> Regards,
> Daniel
>
> >
> > Fascinating - it seems to work on my config, a lightly modified
> > defconfig (attached):
> >
> > [ 111.287854] lkdtm: loop 46/64 ...
> > [ 111.287856] lkdtm: loop 45/64 ...
> > [ 111.287859] lkdtm: loop 44/64 ...
> > [ 111.287862] lkdtm: loop 43/64 ...
> > [ 111.287864] lkdtm: loop 42/64 ...
> > [ 111.287867] lkdtm: loop 41/64 ...
> > [ 111.287869] lkdtm: loop 40/64 ...
> > [ 111.288498] BUG: stack guard page was hit at 000000007bf6ef1a (stack is 000000005952e5cc..00000000ba40316c)
> > [ 111.288499] kernel stack overflow (double-fault): 0000 [#1] SMP KASAN PTI
> > [ 111.288500] CPU: 0 PID: 767 Comm: modprobe Not tainted 5.3.0-rc1-next-20190723+ #91
> > [ 111.288501] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> > [ 111.288501] RIP: 0010:__lock_acquire+0x43/0x3b50
> > [ 111.288503] Code: 84 24 90 00 00 00 48 c7 84 24 90 00 00 00 b3 8a b5 41 48 8b 9c 24 28 01 00 00 48 c7 84 24 98 00 00 00 f8
> > 5a a9 84 48 c1 e8 03 <48> 89 44 24 18 48 89 c7 48 b8 00 00 00 00 00 fc ff df 48 c7 84 24
> > [ 111.288504] RSP: 0018:ffffc90000a37fd8 EFLAGS: 00010802
> > [ 111.288505] RAX: 1ffff9200014700d RBX: 0000000000000000 RCX: 0000000000000000
> > [ 111.288506] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff84cf3ff8
> > [ 111.288507] RBP: ffffffff84cf3ff8 R08: 0000000000000001 R09: 0000000000000001
> > [ 111.288507] R10: fffffbfff0a440cf R11: ffffffff8522067f R12: 0000000000000000
> > [ 111.288508] R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
> > [ 111.288509] FS: 00007f97f1f23740(0000) GS:ffff88806c400000(0000) knlGS:0000000000000000
> > [ 111.288510] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 111.288510] CR2: ffffc90000a37fc8 CR3: 000000006a0fc005 CR4: 0000000000360ef0
> > [ 111.288511] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [ 111.288512] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > [ 111.288512] Call Trace:
> > [ 111.288513] lock_acquire+0x125/0x300
> > [ 111.288513] ? vprintk_emit+0x6c/0x250
> > [ 111.288514] _raw_spin_lock+0x20/0x30
> >
> > I will test with your config and see if I can narrow it down tomorrow.
> >
> > Regards,
> > Daniel
> >
> >
> >
> >> Thanks,
> >> -- Marco
> >>
> >>> > > ---
> >>> > > Documentation/dev-tools/kasan.rst | 60 +++++++++++++++++++++++++++++++
> >>> > > include/linux/kasan.h | 16 +++++++++
> >>> > > lib/Kconfig.kasan | 16 +++++++++
> >>> > > lib/test_kasan.c | 26 ++++++++++++++
> >>> > > mm/kasan/common.c | 51 ++++++++++++++++++++++++++
> >>> > > mm/kasan/generic_report.c | 3 ++
> >>> > > mm/kasan/kasan.h | 1 +
> >>> > > mm/vmalloc.c | 15 +++++++-
> >>> > > 8 files changed, 187 insertions(+), 1 deletion(-)
> >>> > >
> >>> > > diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
> >>> > > index b72d07d70239..35fda484a672 100644
> >>> > > --- a/Documentation/dev-tools/kasan.rst
> >>> > > +++ b/Documentation/dev-tools/kasan.rst
> >>> > > @@ -215,3 +215,63 @@ brk handler is used to print bug reports.
> >>> > > A potential expansion of this mode is a hardware tag-based mode, which would
> >>> > > use hardware memory tagging support instead of compiler instrumentation and
> >>> > > manual shadow memory manipulation.
> >>> > > +
> >>> > > +What memory accesses are sanitised by KASAN?
> >>> > > +--------------------------------------------
> >>> > > +
> >>> > > +The kernel maps memory in a number of different parts of the address
> >>> > > +space. This poses something of a problem for KASAN, which requires
> >>> > > +that all addresses accessed by instrumented code have a valid shadow
> >>> > > +region.
> >>> > > +
> >>> > > +The range of kernel virtual addresses is large: there is not enough
> >>> > > +real memory to support a real shadow region for every address that
> >>> > > +could be accessed by the kernel.
> >>> > > +
> >>> > > +By default
> >>> > > +~~~~~~~~~~
> >>> > > +
> >>> > > +By default, architectures only map real memory over the shadow region
> >>> > > +for the linear mapping (and potentially other small areas). For all
> >>> > > +other areas - such as vmalloc and vmemmap space - a single read-only
> >>> > > +page is mapped over the shadow area. This read-only shadow page
> >>> > > +declares all memory accesses as permitted.
> >>> > > +
> >>> > > +This presents a problem for modules: they do not live in the linear
> >>> > > +mapping, but in a dedicated module space. By hooking in to the module
> >>> > > +allocator, KASAN can temporarily map real shadow memory to cover
> >>> > > +them. This allows detection of invalid accesses to module globals, for
> >>> > > +example.
> >>> > > +
> >>> > > +This also creates an incompatibility with ``VMAP_STACK``: if the stack
> >>> > > +lives in vmalloc space, it will be shadowed by the read-only page, and
> >>> > > +the kernel will fault when trying to set up the shadow data for stack
> >>> > > +variables.
> >>> > > +
> >>> > > +CONFIG_KASAN_VMALLOC
> >>> > > +~~~~~~~~~~~~~~~~~~~~
> >>> > > +
> >>> > > +With ``CONFIG_KASAN_VMALLOC``, KASAN can cover vmalloc space at the
> >>> > > +cost of greater memory usage. Currently this is only supported on x86.
> >>> > > +
> >>> > > +This works by hooking into vmalloc and vmap, and dynamically
> >>> > > +allocating real shadow memory to back the mappings.
> >>> > > +
> >>> > > +Most mappings in vmalloc space are small, requiring less than a full
> >>> > > +page of shadow space. Allocating a full shadow page per mapping would
> >>> > > +therefore be wasteful. Furthermore, to ensure that different mappings
> >>> > > +use different shadow pages, mappings would have to be aligned to
> >>> > > +``KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE``.
> >>> > > +
> >>> > > +Instead, we share backing space across multiple mappings. We allocate
> >>> > > +a backing page the first time a mapping in vmalloc space uses a
> >>> > > +particular page of the shadow region. We keep this page around
> >>> > > +regardless of whether the mapping is later freed - in the mean time
> >>> > > +this page could have become shared by another vmalloc mapping.
> >>> > > +
> >>> > > +This can in theory lead to unbounded memory growth, but the vmalloc
> >>> > > +allocator is pretty good at reusing addresses, so the practical memory
> >>> > > +usage grows at first but then stays fairly stable.
> >>> > > +
> >>> > > +This allows ``VMAP_STACK`` support on x86, and enables support of
> >>> > > +architectures that do not have a fixed module region.
> >>> > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> >>> > > index cc8a03cc9674..fcabc5a03fca 100644
> >>> > > --- a/include/linux/kasan.h
> >>> > > +++ b/include/linux/kasan.h
> >>> > > @@ -70,8 +70,18 @@ struct kasan_cache {
> >>> > > int free_meta_offset;
> >>> > > };
> >>> > >
> >>> > > +/*
> >>> > > + * These functions provide a special case to support backing module
> >>> > > + * allocations with real shadow memory. With KASAN vmalloc, the special
> >>> > > + * case is unnecessary, as the work is handled in the generic case.
> >>> > > + */
> >>> > > +#ifndef CONFIG_KASAN_VMALLOC
> >>> > > int kasan_module_alloc(void *addr, size_t size);
> >>> > > void kasan_free_shadow(const struct vm_struct *vm);
> >>> > > +#else
> >>> > > +static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
> >>> > > +static inline void kasan_free_shadow(const struct vm_struct *vm) {}
> >>> > > +#endif
> >>> > >
> >>> > > int kasan_add_zero_shadow(void *start, unsigned long size);
> >>> > > void kasan_remove_zero_shadow(void *start, unsigned long size);
> >>> > > @@ -194,4 +204,10 @@ static inline void *kasan_reset_tag(const void *addr)
> >>> > >
> >>> > > #endif /* CONFIG_KASAN_SW_TAGS */
> >>> > >
> >>> > > +#ifdef CONFIG_KASAN_VMALLOC
> >>> > > +void kasan_cover_vmalloc(unsigned long requested_size, struct vm_struct *area);
> >>> > > +#else
> >>> > > +static inline void kasan_cover_vmalloc(unsigned long requested_size, struct vm_struct *area) {}
> >>> > > +#endif
> >>> > > +
> >>> > > #endif /* LINUX_KASAN_H */
> >>> > > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> >>> > > index 4fafba1a923b..a320dc2e9317 100644
> >>> > > --- a/lib/Kconfig.kasan
> >>> > > +++ b/lib/Kconfig.kasan
> >>> > > @@ -6,6 +6,9 @@ config HAVE_ARCH_KASAN
> >>> > > config HAVE_ARCH_KASAN_SW_TAGS
> >>> > > bool
> >>> > >
> >>> > > +config HAVE_ARCH_KASAN_VMALLOC
> >>> > > + bool
> >>> > > +
> >>> > > config CC_HAS_KASAN_GENERIC
> >>> > > def_bool $(cc-option, -fsanitize=kernel-address)
> >>> > >
> >>> > > @@ -135,6 +138,19 @@ config KASAN_S390_4_LEVEL_PAGING
> >>> > > to 3TB of RAM with KASan enabled). This options allows to force
> >>> > > 4-level paging instead.
> >>> > >
> >>> > > +config KASAN_VMALLOC
> >>> > > + bool "Back mappings in vmalloc space with real shadow memory"
> >>> > > + depends on KASAN && HAVE_ARCH_KASAN_VMALLOC
> >>> > > + help
> >>> > > + By default, the shadow region for vmalloc space is the read-only
> >>> > > + zero page. This means that KASAN cannot detect errors involving
> >>> > > + vmalloc space.
> >>> > > +
> >>> > > + Enabling this option will hook in to vmap/vmalloc and back those
> >>> > > + mappings with real shadow memory allocated on demand. This allows
> >>> > > + for KASAN to detect more sorts of errors (and to support vmapped
> >>> > > + stacks), but at the cost of higher memory usage.
> >>> > > +
> >>> > > config TEST_KASAN
> >>> > > tristate "Module for testing KASAN for bug detection"
> >>> > > depends on m && KASAN
> >>> > > diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> >>> > > index b63b367a94e8..d375246f5f96 100644
> >>> > > --- a/lib/test_kasan.c
> >>> > > +++ b/lib/test_kasan.c
> >>> > > @@ -18,6 +18,7 @@
> >>> > > #include <linux/slab.h>
> >>> > > #include <linux/string.h>
> >>> > > #include <linux/uaccess.h>
> >>> > > +#include <linux/vmalloc.h>
> >>> > >
> >>> > > /*
> >>> > > * Note: test functions are marked noinline so that their names appear in
> >>> > > @@ -709,6 +710,30 @@ static noinline void __init kmalloc_double_kzfree(void)
> >>> > > kzfree(ptr);
> >>> > > }
> >>> > >
> >>> > > +#ifdef CONFIG_KASAN_VMALLOC
> >>> > > +static noinline void __init vmalloc_oob(void)
> >>> > > +{
> >>> > > + void *area;
> >>> > > +
> >>> > > + pr_info("vmalloc out-of-bounds\n");
> >>> > > +
> >>> > > + /*
> >>> > > + * We have to be careful not to hit the guard page.
> >>> > > + * The MMU will catch that and crash us.
> >>> > > + */
> >>> > > + area = vmalloc(3000);
> >>> > > + if (!area) {
> >>> > > + pr_err("Allocation failed\n");
> >>> > > + return;
> >>> > > + }
> >>> > > +
> >>> > > + ((volatile char *)area)[3100];
> >>> > > + vfree(area);
> >>> > > +}
> >>> > > +#else
> >>> > > +static void __init vmalloc_oob(void) {}
> >>> > > +#endif
> >>> > > +
> >>> > > static int __init kmalloc_tests_init(void)
> >>> > > {
> >>> > > /*
> >>> > > @@ -752,6 +777,7 @@ static int __init kmalloc_tests_init(void)
> >>> > > kasan_strings();
> >>> > > kasan_bitops();
> >>> > > kmalloc_double_kzfree();
> >>> > > + vmalloc_oob();
> >>> > >
> >>> > > kasan_restore_multi_shot(multishot);
> >>> > >
> >>> > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> >>> > > index 2277b82902d8..a3bb84efccbf 100644
> >>> > > --- a/mm/kasan/common.c
> >>> > > +++ b/mm/kasan/common.c
> >>> > > @@ -568,6 +568,7 @@ void kasan_kfree_large(void *ptr, unsigned long ip)
> >>> > > /* The object will be poisoned by page_alloc. */
> >>> > > }
> >>> > >
> >>> > > +#ifndef CONFIG_KASAN_VMALLOC
> >>> > > int kasan_module_alloc(void *addr, size_t size)
> >>> > > {
> >>> > > void *ret;
> >>> > > @@ -603,6 +604,7 @@ void kasan_free_shadow(const struct vm_struct *vm)
> >>> > > if (vm->flags & VM_KASAN)
> >>> > > vfree(kasan_mem_to_shadow(vm->addr));
> >>> > > }
> >>> > > +#endif
> >>> > >
> >>> > > extern void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip);
> >>> > >
> >>> > > @@ -722,3 +724,52 @@ static int __init kasan_memhotplug_init(void)
> >>> > >
> >>> > > core_initcall(kasan_memhotplug_init);
> >>> > > #endif
> >>> > > +
> >>> > > +#ifdef CONFIG_KASAN_VMALLOC
> >>> > > +void kasan_cover_vmalloc(unsigned long requested_size, struct vm_struct *area)
> >>> > > +{
> >>> > > + unsigned long shadow_alloc_start, shadow_alloc_end;
> >>> > > + unsigned long addr;
> >>> > > + unsigned long backing;
> >>> > > + pgd_t *pgdp;
> >>> > > + p4d_t *p4dp;
> >>> > > + pud_t *pudp;
> >>> > > + pmd_t *pmdp;
> >>> > > + pte_t *ptep;
> >>> > > + pte_t backing_pte;
> >>> > > +
> >>> > > + shadow_alloc_start = ALIGN_DOWN(
> >>> > > + (unsigned long)kasan_mem_to_shadow(area->addr),
> >>> > > + PAGE_SIZE);
> >>> > > + shadow_alloc_end = ALIGN(
> >>> > > + (unsigned long)kasan_mem_to_shadow(area->addr + area->size),
> >>> > > + PAGE_SIZE);
> >>> > > +
> >>> > > + addr = shadow_alloc_start;
> >>> > > + do {
> >>> > > + pgdp = pgd_offset_k(addr);
> >>> > > + p4dp = p4d_alloc(&init_mm, pgdp, addr);
> >>> >
> >>> > Page table allocations will be protected by mm->page_table_lock, right?
> >>> >
> >>> >
> >>> > > + pudp = pud_alloc(&init_mm, p4dp, addr);
> >>> > > + pmdp = pmd_alloc(&init_mm, pudp, addr);
> >>> > > + ptep = pte_alloc_kernel(pmdp, addr);
> >>> > > +
> >>> > > + /*
> >>> > > + * we can validly get here if pte is not none: it means we
> >>> > > + * allocated this page earlier to use part of it for another
> >>> > > + * allocation
> >>> > > + */
> >>> > > + if (pte_none(*ptep)) {
> >>> > > + backing = __get_free_page(GFP_KERNEL);
> >>> > > + backing_pte = pfn_pte(PFN_DOWN(__pa(backing)),
> >>> > > + PAGE_KERNEL);
> >>> > > + set_pte_at(&init_mm, addr, ptep, backing_pte);
> >>> > > + }
> >>> > > + } while (addr += PAGE_SIZE, addr != shadow_alloc_end);
> >>> > > +
> >>> > > + requested_size = round_up(requested_size, KASAN_SHADOW_SCALE_SIZE);
> >>> > > + kasan_unpoison_shadow(area->addr, requested_size);
> >>> > > + kasan_poison_shadow(area->addr + requested_size,
> >>> > > + area->size - requested_size,
> >>> > > + KASAN_VMALLOC_INVALID);
> >>> >
> >>> >
> >>> > Do I read this correctly that if kernel code does vmalloc(64), they
> >>> > will have exactly 64 bytes available rather than full page? To make
> >>> > sure: vmalloc does not guarantee that the available size is rounded up
> >>> > to page size? I suspect we will see a throw out of new bugs related to
> >>> > OOBs on vmalloc memory. So I want to make sure that these will be
> >>> > indeed bugs that we agree need to be fixed.
> >>> > I am sure there will be bugs where the size is controlled by
> >>> > user-space, so these are bad bugs under any circumstances. But there
> >>> > will also probably be OOBs, where people will try to "prove" that
> >>> > that's fine and will work (just based on our previous experiences :)).
> >>> >
> >>> > On impl side: kasan_unpoison_shadow seems to be capable of handling
> >>> > non-KASAN_SHADOW_SCALE_SIZE-aligned sizes exactly in the way we want.
> >>> > So I think it's better to do:
> >>> >
> >>> > kasan_unpoison_shadow(area->addr, requested_size);
> >>> > requested_size = round_up(requested_size, KASAN_SHADOW_SCALE_SIZE);
> >>> > kasan_poison_shadow(area->addr + requested_size,
> >>> > area->size - requested_size,
> >>> > KASAN_VMALLOC_INVALID);
> >>> >
> >>> >
> >>> >
> >>> > > +}
> >>> > > +#endif
> >>> > > diff --git a/mm/kasan/generic_report.c b/mm/kasan/generic_report.c
> >>> > > index 36c645939bc9..2d97efd4954f 100644
> >>> > > --- a/mm/kasan/generic_report.c
> >>> > > +++ b/mm/kasan/generic_report.c
> >>> > > @@ -86,6 +86,9 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info)
> >>> > > case KASAN_ALLOCA_RIGHT:
> >>> > > bug_type = "alloca-out-of-bounds";
> >>> > > break;
> >>> > > + case KASAN_VMALLOC_INVALID:
> >>> > > + bug_type = "vmalloc-out-of-bounds";
> >>> > > + break;
> >>> > > }
> >>> > >
> >>> > > return bug_type;
> >>> > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> >>> > > index 014f19e76247..8b1f2fbc780b 100644
> >>> > > --- a/mm/kasan/kasan.h
> >>> > > +++ b/mm/kasan/kasan.h
> >>> > > @@ -25,6 +25,7 @@
> >>> > > #endif
> >>> > >
> >>> > > #define KASAN_GLOBAL_REDZONE 0xFA /* redzone for global variable */
> >>> > > +#define KASAN_VMALLOC_INVALID 0xF9 /* unallocated space in vmapped page */
> >>> > >
> >>> > > /*
> >>> > > * Stack redzone shadow values
> >>> > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> >>> > > index 4fa8d84599b0..8cbcb5056c9b 100644
> >>> > > --- a/mm/vmalloc.c
> >>> > > +++ b/mm/vmalloc.c
> >>> > > @@ -2012,6 +2012,15 @@ static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
> >>> > > va->vm = vm;
> >>> > > va->flags |= VM_VM_AREA;
> >>> > > spin_unlock(&vmap_area_lock);
> >>> > > +
> >>> > > + /*
> >>> > > + * If we are in vmalloc space we need to cover the shadow area with
> >>> > > + * real memory. If we come here through VM_ALLOC, this is done
> >>> > > + * by a higher level function that has access to the true size,
> >>> > > + * which might not be a full page.
> >>> > > + */
> >>> > > + if (is_vmalloc_addr(vm->addr) && !(vm->flags & VM_ALLOC))
> >>> > > + kasan_cover_vmalloc(vm->size, vm);
> >>> > > }
> >>> > >
> >>> > > static void clear_vm_uninitialized_flag(struct vm_struct *vm)
> >>> > > @@ -2483,6 +2492,8 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
> >>> > > if (!addr)
> >>> > > return NULL;
> >>> > >
> >>> > > + kasan_cover_vmalloc(real_size, area);
> >>> > > +
> >>> > > /*
> >>> > > * In this function, newly allocated vm_struct has VM_UNINITIALIZED
> >>> > > * flag. It means that vm_struct is not fully initialized.
> >>> > > @@ -3324,9 +3335,11 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
> >>> > > spin_unlock(&vmap_area_lock);
> >>> > >
> >>> > > /* insert all vm's */
> >>> > > - for (area = 0; area < nr_vms; area++)
> >>> > > + for (area = 0; area < nr_vms; area++) {
> >>> > > setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
> >>> > > pcpu_get_vm_areas);
> >>> > > + kasan_cover_vmalloc(sizes[area], vms[area]);
> >>> > > + }
> >>> > >
> >>> > > kfree(vas);
> >>> > > return vms;
> >>> > > --
> >>> > > 2.20.1
> >>> > >
> >>> > > --
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