[linux-yocto] [PATCH] kmemleak: Turn kmemleak_lock to raw spinlock on RT
Bruce Ashfield
bruce.ashfield at windriver.com
Wed Nov 21 06:54:45 PST 2018
On 2018-11-14 2:27 p.m., Bruce Ashfield wrote:
> On 11/13/18 4:11 AM, zhe.he at windriver.com wrote:
>> From: He Zhe <zhe.he at windriver.com>
>>
>> See https://lore.kernel.org/patchwork/patch/1011368/ for upstream status.
>>
>> kmemleak_lock, as a rwlock on RT, can possibly be held in atomic
>> context and
>> causes the follow BUG.
>
> Thanks. I'm waiting to see if there's any upstream feedback, and
> will wait a couple more days before deciding to merge.
>
> The alternative to making this a raw lock would be to simply declare
> it incompatible with -rt (Which is what we've done with different
> debug mechanisms in the past). Since there really should be relatively
> few (none??) -rt specific kmemleaks, and if you are really concerned
> about -rt, you likely wouldn't be running with it enabled.
I still see no comments on this upstream, so I've gone ahead and merged
this to the 4.18 branches.
Hopefully there won't be any side effects.
Bruce
>
> Bruce
>
>>
>> BUG: scheduling while atomic: migration/15/132/0x00000002
>> Modules linked in: iTCO_wdt iTCO_vendor_support intel_rapl pcc_cpufreq
>> pnd2_edac intel_powerclamp coretemp crct10dif_pclmul crct10dif_common
>> aesni_intel matroxfb_base aes_x86_64 matroxfb_g450 matroxfb_accel
>> crypto_simd matroxfb_DAC1064 cryptd glue_helper g450_pll matroxfb_misc
>> i2c_ismt i2c_i801 acpi_cpufreq
>> Preemption disabled at:
>> [<ffffffff8c927c11>] cpu_stopper_thread+0x71/0x100
>> CPU: 15 PID: 132 Comm: migration/15 Not tainted 4.19.0-rt1-preempt-rt #1
>> Hardware name: Intel Corp. Harcuvar/Server, BIOS
>> HAVLCRB1.X64.0015.D62.1708310404 08/31/2017
>> Call Trace:
>> dump_stack+0x4f/0x6a
>> ? cpu_stopper_thread+0x71/0x100
>> __schedule_bug.cold.16+0x38/0x55
>> __schedule+0x484/0x6c0
>> schedule+0x3d/0xe0
>> rt_spin_lock_slowlock_locked+0x118/0x2a0
>> rt_spin_lock_slowlock+0x57/0x90
>> __rt_spin_lock+0x26/0x30
>> __write_rt_lock+0x23/0x1a0
>> ? intel_pmu_cpu_dying+0x67/0x70
>> rt_write_lock+0x2a/0x30
>> find_and_remove_object+0x1e/0x80
>> delete_object_full+0x10/0x20
>> kmemleak_free+0x32/0x50
>> kfree+0x104/0x1f0
>> ? x86_pmu_starting_cpu+0x30/0x30
>> intel_pmu_cpu_dying+0x67/0x70
>> x86_pmu_dying_cpu+0x1a/0x30
>> cpuhp_invoke_callback+0x92/0x700
>> take_cpu_down+0x70/0xa0
>> multi_cpu_stop+0x62/0xc0
>> ? cpu_stop_queue_work+0x130/0x130
>> cpu_stopper_thread+0x79/0x100
>> smpboot_thread_fn+0x20f/0x2d0
>> kthread+0x121/0x140
>> ? sort_range+0x30/0x30
>> ? kthread_park+0x90/0x90
>> ret_from_fork+0x35/0x40
>>
>> The following call trace, caused by grabbing kmemleak_lock twice, is also
>> observed.
>>
>> kernel BUG at kernel/locking/rtmutex.c:1048!
>> invalid opcode: 0000 [#1] PREEMPT SMP PTI
>> CPU: 5 PID: 689 Comm: mkfs.ext4 Not tainted 4.18.16-rt9-preempt-rt #1
>> Hardware name: Intel Corp. Harcuvar/Server, BIOS
>> HAVLCRB1.X64.0015.D62.1708310404 08/31/2017
>> RIP: 0010:rt_spin_lock_slowlock_locked+0x277/0x2a0
>> Code: e8 5e 64 61 ff e9 bc fe ff ff e8 54 64 61 ff e9 b7 fe ff ff 0f
>> 0b e8 98 57 53 ff e9 43 fe ff ff e8 8e 57 53 ff e9 74 ff ff ff <0f> 0b
>> 0f 0b 0f 0b 48 8b 43 10 48 85 c0 74 06 48 3b 58 38 75 0b 49
>> RSP: 0018:ffff936846d4f3b0 EFLAGS: 00010046
>> RAX: ffff8e3680361e00 RBX: ffffffff83a8b240 RCX: 0000000000000001
>> RDX: 0000000000000000 RSI: ffff8e3680361e00 RDI: ffffffff83a8b258
>> RBP: ffff936846d4f3e8 R08: ffff8e3680361e01 R09: ffffffff82adfdf0
>> R10: ffffffff827ede18 R11: 0000000000000000 R12: ffff936846d4f3f8
>> R13: ffff8e3680361e00 R14: ffff936846d4f3f8 R15: 0000000000000246
>> FS: 00007fc8b6bfd780(0000) GS:ffff8e369f340000(0000)
>> knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 000055fb5659e000 CR3: 00000007fdd14000 CR4: 00000000003406e0
>> Call Trace:
>> ? preempt_count_add+0x74/0xc0
>> rt_spin_lock_slowlock+0x57/0x90
>> ? __kernel_text_address+0x12/0x40
>> ? __save_stack_trace+0x75/0x100
>> __rt_spin_lock+0x26/0x30
>> __write_rt_lock+0x23/0x1a0
>> rt_write_lock+0x2a/0x30
>> create_object+0x17d/0x2b0
>> kmemleak_alloc+0x34/0x50
>> kmem_cache_alloc+0x146/0x220
>> ? mempool_alloc_slab+0x15/0x20
>> mempool_alloc_slab+0x15/0x20
>> mempool_alloc+0x65/0x170
>> sg_pool_alloc+0x21/0x60
>> __sg_alloc_table+0x101/0x160
>> ? sg_free_table_chained+0x30/0x30
>> sg_alloc_table_chained+0x8b/0xb0
>> scsi_init_sgtable+0x31/0x90
>> scsi_init_io+0x44/0x130
>> sd_setup_write_same16_cmnd+0xef/0x150
>> sd_init_command+0x6bf/0xaa0
>> ? cgroup_base_stat_cputime_account_end.isra.0+0x26/0x60
>> ? elv_rb_del+0x2a/0x40
>> scsi_setup_cmnd+0x8e/0x140
>> scsi_prep_fn+0x5d/0x140
>> blk_peek_request+0xda/0x2f0
>> scsi_request_fn+0x33/0x550
>> ? cfq_rb_erase+0x23/0x40
>> __blk_run_queue+0x43/0x60
>> cfq_insert_request+0x2f3/0x5d0
>> __elv_add_request+0x160/0x290
>> blk_flush_plug_list+0x204/0x230
>> schedule+0x87/0xe0
>> __write_rt_lock+0x18b/0x1a0
>> rt_write_lock+0x2a/0x30
>> create_object+0x17d/0x2b0
>> kmemleak_alloc+0x34/0x50
>> __kmalloc_node+0x1cd/0x340
>> alloc_request_size+0x30/0x70
>> mempool_alloc+0x65/0x170
>> ? ioc_lookup_icq+0x54/0x70
>> get_request+0x4e3/0x8d0
>> ? wait_woken+0x80/0x80
>> blk_queue_bio+0x153/0x470
>> generic_make_request+0x1dc/0x3f0
>> submit_bio+0x49/0x140
>> ? next_bio+0x38/0x40
>> submit_bio_wait+0x59/0x90
>> blkdev_issue_discard+0x7a/0xd0
>> ? _raw_spin_unlock_irqrestore+0x18/0x50
>> blk_ioctl_discard+0xc7/0x110
>> blkdev_ioctl+0x57e/0x960
>> ? __wake_up+0x13/0x20
>> block_ioctl+0x3d/0x50
>> do_vfs_ioctl+0xa8/0x610
>> ? vfs_write+0x166/0x1b0
>> ksys_ioctl+0x67/0x90
>> __x64_sys_ioctl+0x1a/0x20
>> do_syscall_64+0x4d/0xf0
>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>
>> kmemleak is an error detecting feature. We would not expect as good
>> performance
>> as without it. As there is no raw rwlock defining helpers, we turn
>> kmemleak_lock
>> to a raw spinlock.
>>
>> Signed-off-by: He Zhe <zhe.he at windriver.com>
>> ---
>> mm/kmemleak.c | 20 ++++++++++----------
>> 1 file changed, 10 insertions(+), 10 deletions(-)
>>
>> diff --git a/mm/kmemleak.c b/mm/kmemleak.c
>> index 9a085d5..2d00961 100644
>> --- a/mm/kmemleak.c
>> +++ b/mm/kmemleak.c
>> @@ -26,7 +26,7 @@
>> *
>> * The following locks and mutexes are used by kmemleak:
>> *
>> - * - kmemleak_lock (rwlock): protects the object_list modifications and
>> + * - kmemleak_lock (raw spinlock): protects the object_list
>> modifications and
>> * accesses to the object_tree_root. The object_list is the main list
>> * holding the metadata (struct kmemleak_object) for the allocated
>> memory
>> * blocks. The object_tree_root is a red black tree used to look-up
>> @@ -197,7 +197,7 @@ static LIST_HEAD(gray_list);
>> /* search tree for object boundaries */
>> static struct rb_root object_tree_root = RB_ROOT;
>> /* rw_lock protecting the access to object_list and object_tree_root */
>> -static DEFINE_RWLOCK(kmemleak_lock);
>> +static DEFINE_RAW_SPINLOCK(kmemleak_lock);
>> /* allocation caches for kmemleak internal data */
>> static struct kmem_cache *object_cache;
>> @@ -491,9 +491,9 @@ static struct kmemleak_object
>> *find_and_get_object(unsigned long ptr, int alias)
>> struct kmemleak_object *object;
>> rcu_read_lock();
>> - read_lock_irqsave(&kmemleak_lock, flags);
>> + raw_spin_lock_irqsave(&kmemleak_lock, flags);
>> object = lookup_object(ptr, alias);
>> - read_unlock_irqrestore(&kmemleak_lock, flags);
>> + raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
>> /* check whether the object is still available */
>> if (object && !get_object(object))
>> @@ -513,13 +513,13 @@ static struct kmemleak_object
>> *find_and_remove_object(unsigned long ptr, int ali
>> unsigned long flags;
>> struct kmemleak_object *object;
>> - write_lock_irqsave(&kmemleak_lock, flags);
>> + raw_spin_lock_irqsave(&kmemleak_lock, flags);
>> object = lookup_object(ptr, alias);
>> if (object) {
>> rb_erase(&object->rb_node, &object_tree_root);
>> list_del_rcu(&object->object_list);
>> }
>> - write_unlock_irqrestore(&kmemleak_lock, flags);
>> + raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
>> return object;
>> }
>> @@ -593,7 +593,7 @@ static struct kmemleak_object
>> *create_object(unsigned long ptr, size_t size,
>> /* kernel backtrace */
>> object->trace_len = __save_stack_trace(object->trace);
>> - write_lock_irqsave(&kmemleak_lock, flags);
>> + raw_spin_lock_irqsave(&kmemleak_lock, flags);
>> min_addr = min(min_addr, ptr);
>> max_addr = max(max_addr, ptr + size);
>> @@ -624,7 +624,7 @@ static struct kmemleak_object
>> *create_object(unsigned long ptr, size_t size,
>> list_add_tail_rcu(&object->object_list, &object_list);
>> out:
>> - write_unlock_irqrestore(&kmemleak_lock, flags);
>> + raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
>> return object;
>> }
>> @@ -1310,7 +1310,7 @@ static void scan_block(void *_start, void *_end,
>> unsigned long *end = _end - (BYTES_PER_POINTER - 1);
>> unsigned long flags;
>> - read_lock_irqsave(&kmemleak_lock, flags);
>> + raw_spin_lock_irqsave(&kmemleak_lock, flags);
>> for (ptr = start; ptr < end; ptr++) {
>> struct kmemleak_object *object;
>> unsigned long pointer;
>> @@ -1367,7 +1367,7 @@ static void scan_block(void *_start, void *_end,
>> spin_unlock(&object->lock);
>> }
>> }
>> - read_unlock_irqrestore(&kmemleak_lock, flags);
>> + raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
>> }
>> /*
>>
>
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