Messages in this thread Patch in this message | | | Subject | Re: list corruption in deferred_split_scan() | From | Yang Shi <> | Date | Mon, 15 Jul 2019 20:00:51 -0700 |
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On 7/15/19 6:36 PM, Qian Cai wrote: > >> On Jul 15, 2019, at 8:22 PM, Yang Shi <yang.shi@linux.alibaba.com> wrote: >> >> >> >> On 7/15/19 2:23 PM, Qian Cai wrote: >>> On Fri, 2019-07-12 at 12:12 -0700, Yang Shi wrote: >>>>> Another possible lead is that without reverting the those commits below, >>>>> kdump >>>>> kernel would always also crash in shrink_slab_memcg() at this line, >>>>> >>>>> map = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_map, true); >>>> This looks a little bit weird. It seems nodeinfo[nid] is NULL? I didn't >>>> think of where nodeinfo was freed but memcg was still online. Maybe a >>>> check is needed: >>> Actually, "memcg" is NULL. >> It sounds weird. shrink_slab() is called in mem_cgroup_iter which does pin the memcg. So, the memcg should not go away. > Well, the commit “mm: shrinker: make shrinker not depend on memcg kmem” changed this line in shrink_slab_memcg(), > > - if (!memcg_kmem_enabled() || !mem_cgroup_online(memcg)) > + if (!mem_cgroup_online(memcg)) > return 0; > > Since the kdump kernel has the parameter “cgroup_disable=memory”, shrink_slab_memcg() will no longer be able to handle NULL memcg from mem_cgroup_iter() as, > > if (mem_cgroup_disabled()) > return NULL;
Aha, yes. memcg_kmem_enabled() implicitly checks !mem_cgroup_disabled(). Thanks for figuring this out. I think we need add mem_cgroup_dsiabled() check before calling shrink_slab_memcg() as below:
diff --git a/mm/vmscan.c b/mm/vmscan.c index a0301ed..2f03c61 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -701,7 +701,7 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, unsigned long ret, freed = 0; struct shrinker *shrinker;
- if (!mem_cgroup_is_root(memcg)) + if (!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg)) return shrink_slab_memcg(gfp_mask, nid, memcg, priority);
if (!down_read_trylock(&shrinker_rwsem)) > >>>> diff --git a/mm/vmscan.c b/mm/vmscan.c >>>> index a0301ed..bacda49 100644 >>>> --- a/mm/vmscan.c >>>> +++ b/mm/vmscan.c >>>> @@ -602,6 +602,9 @@ static unsigned long shrink_slab_memcg(gfp_t >>>> gfp_mask, int nid, >>>> if (!mem_cgroup_online(memcg)) >>>> return 0; >>>> >>>> + if (!memcg->nodeinfo[nid]) >>>> + return 0; >>>> + >>>> if (!down_read_trylock(&shrinker_rwsem)) >>>> return 0; >>>> >>>>> [ 9.072036][ T1] BUG: KASAN: null-ptr-deref in shrink_slab+0x111/0x440 >>>>> [ 9.072036][ T1] Read of size 8 at addr 0000000000000dc8 by task >>>>> swapper/0/1 >>>>> [ 9.072036][ T1] >>>>> [ 9.072036][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.0-next- >>>>> 20190711+ #10 >>>>> [ 9.072036][ T1] Hardware name: HPE ProLiant DL385 Gen10/ProLiant >>>>> DL385 >>>>> Gen10, BIOS A40 01/25/2019 >>>>> [ 9.072036][ T1] Call Trace: >>>>> [ 9.072036][ T1] dump_stack+0x62/0x9a >>>>> [ 9.072036][ T1] __kasan_report.cold.4+0xb0/0xb4 >>>>> [ 9.072036][ T1] ? unwind_get_return_address+0x40/0x50 >>>>> [ 9.072036][ T1] ? shrink_slab+0x111/0x440 >>>>> [ 9.072036][ T1] kasan_report+0xc/0xe >>>>> [ 9.072036][ T1] __asan_load8+0x71/0xa0 >>>>> [ 9.072036][ T1] shrink_slab+0x111/0x440 >>>>> [ 9.072036][ T1] ? mem_cgroup_iter+0x98/0x840 >>>>> [ 9.072036][ T1] ? unregister_shrinker+0x110/0x110 >>>>> [ 9.072036][ T1] ? kasan_check_read+0x11/0x20 >>>>> [ 9.072036][ T1] ? mem_cgroup_protected+0x39/0x260 >>>>> [ 9.072036][ T1] shrink_node+0x31e/0xa30 >>>>> [ 9.072036][ T1] ? shrink_node_memcg+0x1560/0x1560 >>>>> [ 9.072036][ T1] ? ktime_get+0x93/0x110 >>>>> [ 9.072036][ T1] do_try_to_free_pages+0x22f/0x820 >>>>> [ 9.072036][ T1] ? shrink_node+0xa30/0xa30 >>>>> [ 9.072036][ T1] ? kasan_check_read+0x11/0x20 >>>>> [ 9.072036][ T1] ? check_chain_key+0x1df/0x2e0 >>>>> [ 9.072036][ T1] try_to_free_pages+0x242/0x4d0 >>>>> [ 9.072036][ T1] ? do_try_to_free_pages+0x820/0x820 >>>>> [ 9.072036][ T1] __alloc_pages_nodemask+0x9ce/0x1bc0 >>>>> [ 9.072036][ T1] ? gfp_pfmemalloc_allowed+0xc0/0xc0 >>>>> [ 9.072036][ T1] ? unwind_dump+0x260/0x260 >>>>> [ 9.072036][ T1] ? kernel_text_address+0x33/0xc0 >>>>> [ 9.072036][ T1] ? arch_stack_walk+0x8f/0xf0 >>>>> [ 9.072036][ T1] ? ret_from_fork+0x22/0x40 >>>>> [ 9.072036][ T1] alloc_page_interleave+0x18/0x130 >>>>> [ 9.072036][ T1] alloc_pages_current+0xf6/0x110 >>>>> [ 9.072036][ T1] allocate_slab+0x600/0x11f0 >>>>> [ 9.072036][ T1] new_slab+0x46/0x70 >>>>> [ 9.072036][ T1] ___slab_alloc+0x5d4/0x9c0 >>>>> [ 9.072036][ T1] ? create_object+0x3a/0x3e0 >>>>> [ 9.072036][ T1] ? fs_reclaim_acquire.part.15+0x5/0x30 >>>>> [ 9.072036][ T1] ? ___might_sleep+0xab/0xc0 >>>>> [ 9.072036][ T1] ? create_object+0x3a/0x3e0 >>>>> [ 9.072036][ T1] __slab_alloc+0x12/0x20 >>>>> [ 9.072036][ T1] ? __slab_alloc+0x12/0x20 >>>>> [ 9.072036][ T1] kmem_cache_alloc+0x32a/0x400 >>>>> [ 9.072036][ T1] create_object+0x3a/0x3e0 >>>>> [ 9.072036][ T1] kmemleak_alloc+0x71/0xa0 >>>>> [ 9.072036][ T1] kmem_cache_alloc+0x272/0x400 >>>>> [ 9.072036][ T1] ? kasan_check_read+0x11/0x20 >>>>> [ 9.072036][ T1] ? do_raw_spin_unlock+0xa8/0x140 >>>>> [ 9.072036][ T1] acpi_ps_alloc_op+0x76/0x122 >>>>> [ 9.072036][ T1] acpi_ds_execute_arguments+0x2f/0x18d >>>>> [ 9.072036][ T1] acpi_ds_get_package_arguments+0x7d/0x84 >>>>> [ 9.072036][ T1] acpi_ns_init_one_package+0x33/0x61 >>>>> [ 9.072036][ T1] acpi_ns_init_one_object+0xfc/0x189 >>>>> [ 9.072036][ T1] acpi_ns_walk_namespace+0x114/0x1f2 >>>>> [ 9.072036][ T1] ? acpi_ns_init_one_package+0x61/0x61 >>>>> [ 9.072036][ T1] ? acpi_ns_init_one_package+0x61/0x61 >>>>> [ 9.072036][ T1] acpi_walk_namespace+0x9e/0xcb >>>>> [ 9.072036][ T1] ? acpi_sleep_proc_init+0x36/0x36 >>>>> [ 9.072036][ T1] acpi_ns_initialize_objects+0x99/0xed >>>>> [ 9.072036][ T1] ? acpi_ns_find_ini_methods+0xa2/0xa2 >>>>> [ 9.072036][ T1] ? acpi_tb_load_namespace+0x2dc/0x2eb >>>>> [ 9.072036][ T1] acpi_load_tables+0x61/0x80 >>>>> [ 9.072036][ T1] acpi_init+0x10d/0x44b >>>>> [ 9.072036][ T1] ? acpi_sleep_proc_init+0x36/0x36 >>>>> [ 9.072036][ T1] ? bus_uevent_filter+0x16/0x30 >>>>> [ 9.072036][ T1] ? kobject_uevent_env+0x109/0x980 >>>>> [ 9.072036][ T1] ? kernfs_get+0x13/0x20 >>>>> [ 9.072036][ T1] ? kobject_uevent+0xb/0x10 >>>>> [ 9.072036][ T1] ? kset_register+0x31/0x50 >>>>> [ 9.072036][ T1] ? kset_create_and_add+0x9f/0xd0 >>>>> [ 9.072036][ T1] ? acpi_sleep_proc_init+0x36/0x36 >>>>> [ 9.072036][ T1] do_one_initcall+0xfe/0x45a >>>>> [ 9.072036][ T1] ? initcall_blacklisted+0x150/0x150 >>>>> [ 9.072036][ T1] ? rwsem_down_read_slowpath+0x930/0x930 >>>>> [ 9.072036][ T1] ? kasan_check_write+0x14/0x20 >>>>> [ 9.072036][ T1] ? up_write+0x6b/0x190 >>>>> [ 9.072036][ T1] kernel_init_freeable+0x614/0x6a7 >>>>> [ 9.072036][ T1] ? rest_init+0x188/0x188 >>>>> [ 9.072036][ T1] kernel_init+0x11/0x138 >>>>> [ 9.072036][ T1] ? rest_init+0x188/0x188 >>>>> [ 9.072036][ T1] ret_from_fork+0x22/0x40 >>>>> [ 9.072036][ T1] >>>>> ================================================================== >>>>> [ 9.072036][ T1] Disabling lock debugging due to kernel taint >>>>> [ 9.145712][ T1] BUG: kernel NULL pointer dereference, address: >>>>> 0000000000000dc8 >>>>> [ 9.152036][ T1] #PF: supervisor read access in kernel mode >>>>> [ 9.152036][ T1] #PF: error_code(0x0000) - not-present page >>>>> [ 9.152036][ T1] PGD 0 P4D 0 >>>>> [ 9.152036][ T1] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI >>>>> [ 9.152036][ T1] CPU: 0 PID: 1 Comm: swapper/0 Tainted: >>>>> G B 5.2.0-next-20190711+ #10 >>>>> [ 9.152036][ T1] Hardware name: HPE ProLiant DL385 Gen10/ProLiant >>>>> DL385 >>>>> Gen10, BIOS A40 01/25/2019 >>>>> [ 9.152036][ T1] RIP: 0010:shrink_slab+0x111/0x440 >>>>> [ 9.152036][ T1] Code: c7 20 8d 44 82 e8 7f 8b e8 ff 85 c0 0f 84 e2 02 >>>>> 00 >>>>> 00 4c 63 a5 4c ff ff ff 49 81 c4 b8 01 00 00 4b 8d 7c e6 08 e8 3f 07 0e 00 >>>>> <4f> >>>>> 8b 64 e6 08 49 8d bc 24 20 03 00 00 e8 2d 07 0e 00 49 8b 84 24 >>>>> [ 9.152036][ T1] RSP: 0018:ffff88905757f100 EFLAGS: 00010282 >>>>> [ 9.152036][ T1] RAX: 0000000000000000 RBX: ffff88905757f1b0 RCX: >>>>> ffffffff8112f288 >>>>> [ 9.152036][ T1] RDX: 1ffffffff049c088 RSI: dffffc0000000000 RDI: >>>>> ffffffff824e0440 >>>>> [ 9.152036][ T1] RBP: ffff88905757f1d8 R08: fffffbfff049c089 R09: >>>>> fffffbfff049c088 >>>>> [ 9.152036][ T1] R10: fffffbfff049c088 R11: ffffffff824e0443 R12: >>>>> 00000000000001b8 >>>>> [ 9.152036][ T1] R13: 0000000000000000 R14: 0000000000000000 R15: >>>>> ffff88905757f440 >>>>> [ 9.152036][ T1] FS: 0000000000000000(0000) GS:ffff889062800000(0000) >>>>> knlGS:0000000000000000 >>>>> [ 9.152036][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>> [ 9.152036][ T1] CR2: 0000000000000dc8 CR3: 0000001070212000 CR4: >>>>> 00000000001406b0 >>>>> [ 9.152036][ T1] Call Trace: >>>>> [ 9.152036][ T1] ? mem_cgroup_iter+0x98/0x840 >>>>> [ 9.152036][ T1] ? unregister_shrinker+0x110/0x110 >>>>> [ 9.152036][ T1] ? kasan_check_read+0x11/0x20 >>>>> [ 9.152036][ T1] ? mem_cgroup_protected+0x39/0x260 >>>>> [ 9.152036][ T1] shrink_node+0x31e/0xa30 >>>>> [ 9.152036][ T1] ? shrink_node_memcg+0x1560/0x1560 >>>>> [ 9.152036][ T1] ? ktime_get+0x93/0x110 >>>>> [ 9.152036][ T1] do_try_to_free_pages+0x22f/0x820 >>>>> [ 9.152036][ T1] ? shrink_node+0xa30/0xa30 >>>>> [ 9.152036][ T1] ? kasan_check_read+0x11/0x20 >>>>> [ 9.152036][ T1] ? check_chain_key+0x1df/0x2e0 >>>>> [ 9.152036][ T1] try_to_free_pages+0x242/0x4d0 >>>>> [ 9.152036][ T1] ? do_try_to_free_pages+0x820/0x820 >>>>> [ 9.152036][ T1] __alloc_pages_nodemask+0x9ce/0x1bc0 >>>>> [ 9.152036][ T1] ? gfp_pfmemalloc_allowed+0xc0/0xc0 >>>>> [ 9.152036][ T1] ? unwind_dump+0x260/0x260 >>>>> [ 9.152036][ T1] ? kernel_text_address+0x33/0xc0 >>>>> [ 9.152036][ T1] ? arch_stack_walk+0x8f/0xf0 >>>>> [ 9.152036][ T1] ? ret_from_fork+0x22/0x40 >>>>> [ 9.152036][ T1] alloc_page_interleave+0x18/0x130 >>>>> [ 9.152036][ T1] alloc_pages_current+0xf6/0x110 >>>>> [ 9.152036][ T1] allocate_slab+0x600/0x11f0 >>>>> [ 9.152036][ T1] new_slab+0x46/0x70 >>>>> [ 9.152036][ T1] ___slab_alloc+0x5d4/0x9c0 >>>>> [ 9.152036][ T1] ? create_object+0x3a/0x3e0 >>>>> [ 9.152036][ T1] ? fs_reclaim_acquire.part.15+0x5/0x30 >>>>> [ 9.152036][ T1] ? ___might_sleep+0xab/0xc0 >>>>> [ 9.152036][ T1] ? create_object+0x3a/0x3e0 >>>>> [ 9.152036][ T1] __slab_alloc+0x12/0x20 >>>>> [ 9.152036][ T1] ? __slab_alloc+0x12/0x20 >>>>> [ 9.152036][ T1] kmem_cache_alloc+0x32a/0x400 >>>>> [ 9.152036][ T1] create_object+0x3a/0x3e0 >>>>> [ 9.152036][ T1] kmemleak_alloc+0x71/0xa0 >>>>> [ 9.152036][ T1] kmem_cache_alloc+0x272/0x400 >>>>> [ 9.152036][ T1] ? kasan_check_read+0x11/0x20 >>>>> [ 9.152036][ T1] ? do_raw_spin_unlock+0xa8/0x140 >>>>> [ 9.152036][ T1] acpi_ps_alloc_op+0x76/0x122 >>>>> [ 9.152036][ T1] acpi_ds_execute_arguments+0x2f/0x18d >>>>> [ 9.152036][ T1] acpi_ds_get_package_arguments+0x7d/0x84 >>>>> [ 9.152036][ T1] acpi_ns_init_one_package+0x33/0x61 >>>>> [ 9.152036][ T1] acpi_ns_init_one_object+0xfc/0x189 >>>>> [ 9.152036][ T1] acpi_ns_walk_namespace+0x114/0x1f2 >>>>> [ 9.152036][ T1] ? acpi_ns_init_one_package+0x61/0x61 >>>>> [ 9.152036][ T1] ? acpi_ns_init_one_package+0x61/0x61 >>>>> [ 9.152036][ T1] acpi_walk_namespace+0x9e/0xcb >>>>> [ 9.152036][ T1] ? acpi_sleep_proc_init+0x36/0x36 >>>>> [ 9.152036][ T1] acpi_ns_initialize_objects+0x99/0xed >>>>> [ 9.152036][ T1] ? acpi_ns_find_ini_methods+0xa2/0xa2 >>>>> [ 9.152036][ T1] ? acpi_tb_load_namespace+0x2dc/0x2eb >>>>> [ 9.152036][ T1] acpi_load_tables+0x61/0x80 >>>>> [ 9.152036][ T1] acpi_init+0x10d/0x44b >>>>> [ 9.152036][ T1] ? acpi_sleep_proc_init+0x36/0x36 >>>>> [ 9.152036][ T1] ? bus_uevent_filter+0x16/0x30 >>>>> [ 9.152036][ T1] ? kobject_uevent_env+0x109/0x980 >>>>> [ 9.152036][ T1] ? kernfs_get+0x13/0x20 >>>>> [ 9.152036][ T1] ? kobject_uevent+0xb/0x10 >>>>> [ 9.152036][ T1] ? kset_register+0x31/0x50 >>>>> [ 9.152036][ T1] ? kset_create_and_add+0x9f/0xd0 >>>>> [ 9.152036][ T1] ? acpi_sleep_proc_init+0x36/0x36 >>>>> [ 9.152036][ T1] do_one_initcall+0xfe/0x45a >>>>> [ 9.152036][ T1] ? initcall_blacklisted+0x150/0x150 >>>>> [ 9.152036][ T1] ? rwsem_down_read_slowpath+0x930/0x930 >>>>> [ 9.152036][ T1] ? kasan_check_write+0x14/0x20 >>>>> [ 9.152036][ T1] ? up_write+0x6b/0x190 >>>>> [ 9.152036][ T1] kernel_init_freeable+0x614/0x6a7 >>>>> [ 9.152036][ T1] ? rest_init+0x188/0x188 >>>>> [ 9.152036][ T1] kernel_init+0x11/0x138 >>>>> [ 9.152036][ T1] ? rest_init+0x188/0x188 >>>>> [ 9.152036][ T1] ret_from_fork+0x22/0x40 >>>>> [ 9.152036][ T1] Modules linked in: >>>>> [ 9.152036][ T1] CR2: 0000000000000dc8 >>>>> [ 9.152036][ T1] ---[ end trace 568acce4eca01945 ]--- >>>>> [ 9.152036][ T1] RIP: 0010:shrink_slab+0x111/0x440 >>>>> [ 9.152036][ T1] Code: c7 20 8d 44 82 e8 7f 8b e8 ff 85 c0 0f 84 e2 02 >>>>> 00 >>>>> 00 4c 63 a5 4c ff ff ff 49 81 c4 b8 01 00 00 4b 8d 7c e6 08 e8 3f 07 0e 00 >>>>> <4f> >>>>> 8b 64 e6 08 49 8d bc 24 20 03 00 00 e8 2d 07 0e 00 49 8b 84 24 >>>>> [ 9.152036][ T1] RSP: 0018:ffff88905757f100 EFLAGS: 00010282 >>>>> [ 9.152036][ T1] RAX: 0000000000000000 RBX: ffff88905757f1b0 RCX: >>>>> ffffffff8112f288 >>>>> [ 9.152036][ T1] RDX: 1ffffffff049c088 RSI: dffffc0000000000 RDI: >>>>> ffffffff824e0440 >>>>> [ 9.152036][ T1] RBP: ffff88905757f1d8 R08: fffffbfff049c089 R09: >>>>> fffffbfff049c088 >>>>> [ 9.152036][ T1] R10: fffffbfff049c088 R11: ffffffff824e0443 R12: >>>>> 00000000000001b8 >>>>> [ 9.152036][ T1] R13: 0000000000000000 R14: 0000000000000000 R15: >>>>> ffff88905757f440 >>>>> [ 9.152036][ T1] FS: 0000000000000000(0000) GS:ffff889062800000(0000) >>>>> knlGS:00000000 >>>>>
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