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mm/slub: Add Support for free path information of an object 

This commit adds enables a stack dump for the last free of an object:

slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at meminfo_proc_show+0x40/0x4fc
[   20.192078]     meminfo_proc_show+0x40/0x4fc
[   20.192263]     seq_read_iter+0x18c/0x4c4
[   20.192430]     proc_reg_read_iter+0x84/0xac
[   20.192617]     generic_file_splice_read+0xe8/0x17c
[   20.192816]     splice_direct_to_actor+0xb8/0x290
[   20.193008]     do_splice_direct+0xa0/0xe0
[   20.193185]     do_sendfile+0x2d0/0x438
[   20.193345]     sys_sendfile64+0x12c/0x140
[   20.193523]     ret_fast_syscall+0x0/0x58
[   20.193695]     0xbeeacde4
[   20.193822]  Free path:
[   20.193935]     meminfo_proc_show+0x5c/0x4fc
[   20.194115]     seq_read_iter+0x18c/0x4c4
[   20.194285]     proc_reg_read_iter+0x84/0xac
[   20.194475]     generic_file_splice_read+0xe8/0x17c
[   20.194685]     splice_direct_to_actor+0xb8/0x290
[   20.194870]     do_splice_direct+0xa0/0xe0
[   20.195014]     do_sendfile+0x2d0/0x438
[   20.195174]     sys_sendfile64+0x12c/0x140
[   20.195336]     ret_fast_syscall+0x0/0x58
[   20.195491]     0xbeeacde4

Acked-by: Vlastimil Babka <vbabka@suse.cz>
Co-developed-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Maninder Singh 2021-03-16 16:07:11 +05:30 committed by Paul E. McKenney
parent 0cbc124bce
commit e548eaa116
4 changed files with 20 additions and 2 deletions
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1
mm/slab.h
View File

@ -640,6 +640,7 @@ struct kmem_obj_info {
struct kmem_cache *kp_slab_cache;
void *kp_ret;
void *kp_stack[KS_ADDRS_COUNT];
void *kp_free_stack[KS_ADDRS_COUNT];
};
void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page);
#endif

12
mm/slab_common.c
View File

@ -564,7 +564,7 @@ EXPORT_SYMBOL_GPL(kmem_valid_obj);
* depends on the type of object and on how much debugging is enabled.
* For a slab-cache object, the fact that it is a slab object is printed,
* and, if available, the slab name, return address, and stack trace from
* the allocation of that object.
* the allocation and last free path of that object.
*
* This function will splat if passed a pointer to a non-slab object.
* If you are not sure what type of object you have, you should instead
@ -609,6 +609,16 @@ void kmem_dump_obj(void *object)
break;
pr_info(" %pS\n", kp.kp_stack[i]);
}
if (kp.kp_free_stack[0])
pr_cont(" Free path:\n");
for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
if (!kp.kp_free_stack[i])
break;
pr_info(" %pS\n", kp.kp_free_stack[i]);
}
}
EXPORT_SYMBOL_GPL(kmem_dump_obj);
#endif

7
mm/slub.c
View File

@ -4011,6 +4011,13 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
if (!kpp->kp_stack[i])
break;
}
trackp = get_track(s, objp, TRACK_FREE);
for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
kpp->kp_free_stack[i] = (void *)trackp->addrs[i];
if (!kpp->kp_free_stack[i])
break;
}
#endif
#endif
}

2
mm/util.c
View File

@ -983,7 +983,7 @@ int __weak memcmp_pages(struct page *page1, struct page *page2)
* depends on the type of object and on how much debugging is enabled.
* For example, for a slab-cache object, the slab name is printed, and,
* if available, the return address and stack trace from the allocation
* of that object.
* and last free path of that object.
*/
void mem_dump_obj(void *object)
{