[linux-yocto] [PATCH] kmemleak: Turn kmemleak_lock to raw spinlock on RT
Bruce Ashfield
bruce.ashfield at windriver.com
Wed Nov 14 11:27:37 PST 2018
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.
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);
> }
>
> /*
>
More information about the linux-yocto
mailing list