mainline inclusion from mainline-v6.7-rc1 commit 5e4fc577db2514fee3cc2729415d0e2589d5d056 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IBE0E0
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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delete_object_part() can be called by multiple callers in the same time. If an object is found and removed by a caller, and then another caller try to find it too, it failed and return directly. It still be recorded by kmemleak even if it has already been freed to buddy. With DEBUG on, kmemleak will report the following warning,
kmemleak: Partially freeing unknown object at 0xa1af86000 (size 4096) CPU: 0 PID: 742 Comm: test_huge Not tainted 6.6.0-rc3kmemleak+ #54 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x37/0x50 kmemleak_free_part_phys+0x50/0x60 hugetlb_vmemmap_optimize+0x172/0x290 ? __pfx_vmemmap_remap_pte+0x10/0x10 __prep_new_hugetlb_folio+0xe/0x30 prep_new_hugetlb_folio.isra.0+0xe/0x40 alloc_fresh_hugetlb_folio+0xc3/0xd0 alloc_surplus_hugetlb_folio.constprop.0+0x6e/0xd0 hugetlb_acct_memory.part.0+0xe6/0x2a0 hugetlb_reserve_pages+0x110/0x2c0 hugetlbfs_file_mmap+0x11d/0x1b0 mmap_region+0x248/0x9a0 ? hugetlb_get_unmapped_area+0x15c/0x2d0 do_mmap+0x38b/0x580 vm_mmap_pgoff+0xe6/0x190 ksys_mmap_pgoff+0x18a/0x1f0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Expand __create_object() and move __alloc_object() to the beginning. Then use kmemleak_lock to protect __find_and_remove_object() and __link_object() as a whole, which can guarantee all objects are processed sequentialally.
Link: https://lkml.kernel.org/r/20231018102952.3339837-8-liushixin2@huawei.com Fixes: 53238a60dd4a ("kmemleak: Allow partial freeing of memory blocks") Signed-off-by: Liu Shixin liushixin2@huawei.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: Patrick Wang patrick.wang.shcn@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- mm/kmemleak.c | 42 +++++++++++++++++++++++++++++++----------- 1 file changed, 31 insertions(+), 11 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 39ea73364282..7d210dd74381 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -816,16 +816,25 @@ static void delete_object_full(unsigned long ptr) */ static void delete_object_part(unsigned long ptr, size_t size, bool is_phys) { - struct kmemleak_object *object; - unsigned long start, end; + struct kmemleak_object *object, *object_l, *object_r; + unsigned long start, end, flags; + + object_l = __alloc_object(GFP_KERNEL); + if (!object_l) + return;
- object = find_and_remove_object(ptr, 1, is_phys); + object_r = __alloc_object(GFP_KERNEL); + if (!object_r) + goto out; + + raw_spin_lock_irqsave(&kmemleak_lock, flags); + object = __find_and_remove_object(ptr, 1, is_phys); if (!object) { #ifdef DEBUG kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", ptr, size); #endif - return; + goto unlock; }
/* @@ -835,14 +844,25 @@ static void delete_object_part(unsigned long ptr, size_t size, bool is_phys) */ start = object->pointer; end = object->pointer + object->size; - if (ptr > start) - __create_object(start, ptr - start, object->min_count, - GFP_KERNEL, is_phys); - if (ptr + size < end) - __create_object(ptr + size, end - ptr - size, object->min_count, - GFP_KERNEL, is_phys); + if ((ptr > start) && + !__link_object(object_l, start, ptr - start, + object->min_count, is_phys)) + object_l = NULL; + if ((ptr + size < end) && + !__link_object(object_r, ptr + size, end - ptr - size, + object->min_count, is_phys)) + object_r = NULL; + +unlock: + raw_spin_unlock_irqrestore(&kmemleak_lock, flags); + if (object) + __delete_object(object);
- __delete_object(object); +out: + if (object_l) + mem_pool_free(object_l); + if (object_r) + mem_pool_free(object_r); }
static void __paint_it(struct kmemleak_object *object, int color)