From 98f180837a896ecedf8f7e12af22b57f271d43c9 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 8 Dec 2020 16:13:57 -0800 Subject: [PATCH] mm: Make mem_dump_obj() handle vmalloc() memory This commit adds vmalloc() support to mem_dump_obj(). Note that the vmalloc_dump_obj() function combines the checking and dumping, in contrast with the split between kmem_valid_obj() and kmem_dump_obj(). The reason for the difference is that the checking in the vmalloc() case involves acquiring a global lock, and redundant acquisitions of global locks should be avoided, even on not-so-fast paths. Note that this change causes on-stack variables to be reported as vmalloc() storage from kernel_clone() or similar, depending on the degree of inlining that your compiler does. This is likely more helpful than the earlier "non-paged (local) memory". Cc: Andrew Morton Cc: Joonsoo Kim Cc: Reported-by: Andrii Nakryiko Acked-by: Vlastimil Babka Tested-by: Naresh Kamboju Signed-off-by: Paul E. McKenney --- include/linux/vmalloc.h | 6 ++++++ mm/util.c | 14 ++++++++------ mm/vmalloc.c | 12 ++++++++++++ 3 files changed, 26 insertions(+), 6 deletions(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 80c0181c411d..c18f4751a704 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -246,4 +246,10 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) int register_vmap_purge_notifier(struct notifier_block *nb); int unregister_vmap_purge_notifier(struct notifier_block *nb); +#ifdef CONFIG_MMU +bool vmalloc_dump_obj(void *object); +#else +static inline bool vmalloc_dump_obj(void *object) { return false; } +#endif + #endif /* _LINUX_VMALLOC_H */ diff --git a/mm/util.c b/mm/util.c index 92f23d2c1277..54870226cea6 100644 --- a/mm/util.c +++ b/mm/util.c @@ -996,18 +996,20 @@ int __weak memcmp_pages(struct page *page1, struct page *page2) */ void mem_dump_obj(void *object) { + if (kmem_valid_obj(object)) { + kmem_dump_obj(object); + return; + } + if (vmalloc_dump_obj(object)) + return; if (!virt_addr_valid(object)) { if (object == NULL) pr_cont(" NULL pointer.\n"); else if (object == ZERO_SIZE_PTR) pr_cont(" zero-size pointer.\n"); else - pr_cont(" non-paged (local) memory.\n"); + pr_cont(" non-paged memory.\n"); return; } - if (kmem_valid_obj(object)) { - kmem_dump_obj(object); - return; - } - pr_cont(" non-slab memory.\n"); + pr_cont(" non-slab/vmalloc memory.\n"); } diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 4d88fe5a277a..c274ea4f14ea 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3448,6 +3448,18 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) } #endif /* CONFIG_SMP */ +bool vmalloc_dump_obj(void *object) +{ + struct vm_struct *vm; + void *objp = (void *)PAGE_ALIGN((unsigned long)object); + + vm = find_vm_area(objp); + if (!vm) + return false; + pr_cont(" vmalloc allocated at %pS\n", vm->caller); + return true; +} + #ifdef CONFIG_PROC_FS static void *s_start(struct seq_file *m, loff_t *pos) __acquires(&vmap_purge_lock)