| Message ID | 1615891032-29160-1-git-send-email-maninder1.s@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/3] mm/slub: fixing backtrace of objects because of redzone adjustment | expand |
On Tue, Mar 16, 2021 at 04:07:10PM +0530, Maninder Singh wrote: > fixing commit 8e7f37f2aaa5 ("mm: Add mem_dump_obj() to print source > of memory block") > > with current code, Backtrace of allocated object is coming wrong: > / # cat /proc/meminfo > [ 14.969843] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at 0x6b6b6b6b > [ 14.970635] 0x6b6b6b6b > [ 14.970794] 0x6b6b6b6b > [ 14.970932] 0x6b6b6b6b > [ 14.971077] 0x6b6b6b6b > [ 14.971202] 0x6b6b6b6b > [ 14.971317] 0x6b6b6b6b > [ 14.971423] 0x6b6b6b6b > [ 14.971635] 0x6b6b6b6b > [ 14.971740] 0x6b6b6b6b > [ 14.971871] 0x6b6b6b6b > [ 14.972229] 0x6b6b6b6b > [ 14.972363] 0x6b6b6b6b > [ 14.972505] 0xa56b6b6b > [ 14.972631] 0xbbbbbbbb > [ 14.972734] 0xc8ab0400 > [ 14.972891] meminfo_proc_show+0x40/0x4fc > > And reason is red zone was not adjusted from object address. > after adding fixup for redzone, backtrace is coming correct: > / # cat /proc/meminfo > [ 14.870782] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 128 size 64 allocated at meminfo_proc_show+0x40/0x4f4 > [ 14.871817] meminfo_proc_show+0x40/0x4f4 > [ 14.872035] seq_read_iter+0x18c/0x4c4 > [ 14.872229] proc_reg_read_iter+0x84/0xac > [ 14.872433] generic_file_splice_read+0xe8/0x17c > [ 14.872621] splice_direct_to_actor+0xb8/0x290 > [ 14.872747] do_splice_direct+0xa0/0xe0 > [ 14.872896] do_sendfile+0x2d0/0x438 > [ 14.873044] sys_sendfile64+0x12c/0x140 > [ 14.873229] ret_fast_syscall+0x0/0x58 > [ 14.873372] 0xbe861de4 > > Signed-off-by: Vaneet Narang <v.narang@samsung.com> > Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Good catch, thank you! For the series: Acked-by: Paul E. McKenney <paulmck@kernel.org> On the other hand, if you would like me to take these, we need to get a maintainer ack. Thanx, Paul > --- > mm/slub.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/slub.c b/mm/slub.c > index 1912c4614248..9d13f0117ae6 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -4052,6 +4052,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) > !(s->flags & SLAB_STORE_USER)) > return; > #ifdef CONFIG_SLUB_DEBUG > + objp = fixup_red_left(s, objp); > trackp = get_track(s, objp, TRACK_ALLOC); > kpp->kp_ret = (void *)trackp->addr; > #ifdef CONFIG_STACKTRACE > -- > 2.17.1 >
On 3/16/21 11:37 AM, Maninder Singh wrote: > fixing commit 8e7f37f2aaa5 ("mm: Add mem_dump_obj() to print source > of memory block") > > with current code, Backtrace of allocated object is coming wrong: > / # cat /proc/meminfo > [ 14.969843] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at 0x6b6b6b6b > [ 14.970635] 0x6b6b6b6b > [ 14.970794] 0x6b6b6b6b > [ 14.970932] 0x6b6b6b6b > [ 14.971077] 0x6b6b6b6b > [ 14.971202] 0x6b6b6b6b > [ 14.971317] 0x6b6b6b6b > [ 14.971423] 0x6b6b6b6b > [ 14.971635] 0x6b6b6b6b > [ 14.971740] 0x6b6b6b6b > [ 14.971871] 0x6b6b6b6b > [ 14.972229] 0x6b6b6b6b > [ 14.972363] 0x6b6b6b6b > [ 14.972505] 0xa56b6b6b > [ 14.972631] 0xbbbbbbbb > [ 14.972734] 0xc8ab0400 > [ 14.972891] meminfo_proc_show+0x40/0x4fc > > And reason is red zone was not adjusted from object address. > after adding fixup for redzone, backtrace is coming correct: > / # cat /proc/meminfo > [ 14.870782] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 128 size 64 allocated at meminfo_proc_show+0x40/0x4f4 > [ 14.871817] meminfo_proc_show+0x40/0x4f4 > [ 14.872035] seq_read_iter+0x18c/0x4c4 > [ 14.872229] proc_reg_read_iter+0x84/0xac > [ 14.872433] generic_file_splice_read+0xe8/0x17c > [ 14.872621] splice_direct_to_actor+0xb8/0x290 > [ 14.872747] do_splice_direct+0xa0/0xe0 > [ 14.872896] do_sendfile+0x2d0/0x438 > [ 14.873044] sys_sendfile64+0x12c/0x140 > [ 14.873229] ret_fast_syscall+0x0/0x58 > [ 14.873372] 0xbe861de4 > > Signed-off-by: Vaneet Narang <v.narang@samsung.com> > Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> > --- > mm/slub.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/slub.c b/mm/slub.c > index 1912c4614248..9d13f0117ae6 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -4052,6 +4052,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) > !(s->flags & SLAB_STORE_USER)) > return; > #ifdef CONFIG_SLUB_DEBUG > + objp = fixup_red_left(s, objp); > trackp = get_track(s, objp, TRACK_ALLOC); > kpp->kp_ret = (void *)trackp->addr; > #ifdef CONFIG_STACKTRACE >
diff --git a/mm/slub.c b/mm/slub.c index 1912c4614248..9d13f0117ae6 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -4052,6 +4052,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) !(s->flags & SLAB_STORE_USER)) return; #ifdef CONFIG_SLUB_DEBUG + objp = fixup_red_left(s, objp); trackp = get_track(s, objp, TRACK_ALLOC); kpp->kp_ret = (void *)trackp->addr; #ifdef CONFIG_STACKTRACE
fixing commit 8e7f37f2aaa5 ("mm: Add mem_dump_obj() to print source of memory block") with current code, Backtrace of allocated object is coming wrong: / # cat /proc/meminfo [ 14.969843] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at 0x6b6b6b6b [ 14.970635] 0x6b6b6b6b [ 14.970794] 0x6b6b6b6b [ 14.970932] 0x6b6b6b6b [ 14.971077] 0x6b6b6b6b [ 14.971202] 0x6b6b6b6b [ 14.971317] 0x6b6b6b6b [ 14.971423] 0x6b6b6b6b [ 14.971635] 0x6b6b6b6b [ 14.971740] 0x6b6b6b6b [ 14.971871] 0x6b6b6b6b [ 14.972229] 0x6b6b6b6b [ 14.972363] 0x6b6b6b6b [ 14.972505] 0xa56b6b6b [ 14.972631] 0xbbbbbbbb [ 14.972734] 0xc8ab0400 [ 14.972891] meminfo_proc_show+0x40/0x4fc And reason is red zone was not adjusted from object address. after adding fixup for redzone, backtrace is coming correct: / # cat /proc/meminfo [ 14.870782] slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 128 size 64 allocated at meminfo_proc_show+0x40/0x4f4 [ 14.871817] meminfo_proc_show+0x40/0x4f4 [ 14.872035] seq_read_iter+0x18c/0x4c4 [ 14.872229] proc_reg_read_iter+0x84/0xac [ 14.872433] generic_file_splice_read+0xe8/0x17c [ 14.872621] splice_direct_to_actor+0xb8/0x290 [ 14.872747] do_splice_direct+0xa0/0xe0 [ 14.872896] do_sendfile+0x2d0/0x438 [ 14.873044] sys_sendfile64+0x12c/0x140 [ 14.873229] ret_fast_syscall+0x0/0x58 [ 14.873372] 0xbe861de4 Signed-off-by: Vaneet Narang <v.narang@samsung.com> Signed-off-by: Maninder Singh <maninder1.s@samsung.com> --- mm/slub.c | 1 + 1 file changed, 1 insertion(+)