Commit e548eaa1 authored by Maninder Singh's avatar Maninder Singh Committed by Paul E. McKenney
Browse files

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: default avatarVlastimil Babka <vbabka@suse.cz>
Co-developed-by: default avatarVaneet Narang <v.narang@samsung.com>
Signed-off-by: default avatarVaneet Narang <v.narang@samsung.com>
Signed-off-by: default avatarManinder Singh <maninder1.s@samsung.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 0cbc124b

mm/slab.h

+1 −0
Original line number Diff line number Diff line
@@ -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

mm/slab_common.c

+11 −1
Original line number Diff line number Diff line
@@ -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

mm/slub.c

+7 −0
Original line number Diff line number Diff line
@@ -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

}

mm/util.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

{