On 2018/11/21 22:54, Bruce Ashfield wrote: > On 2018-11-14 2:27 p.m., Bruce Ashfield wrote: >> On 11/13/18 4:11 AM, zhe...@windriver.com wrote: >>> From: He Zhe <zhe...@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.
OK, thanks. I'll keep an eye on it. Zhe > > 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...@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); >>> } >>> /* >>> >> > > -- _______________________________________________ linux-yocto mailing list linux-yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/linux-yocto