Messages in this thread | | | Subject | Re: [PATCH -next] blk-mq: fix warning when unregister mq sysfs | From | "yebin (H)" <> | Date | Tue, 15 Nov 2022 22:18:17 +0800 |
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On 2022/11/14 10:07, Ming Lei wrote: > On Sat, Nov 12, 2022 at 04:28:13PM +0800, Ye Bin wrote: >> From: Ye Bin <yebin10@huawei.com> >> >> There's issue as follows when do fault injection test: >> ------------[ cut here ]------------ >> kernfs: can not remove 'nr_tags', no directory >> WARNING: CPU: 8 PID: 2308 at fs/kernfs/dir.c:1635 kernfs_remove_by_name_ns+0xdd/0x100 >> Modules linked in: null_blk(-) >> CPU: 8 PID: 2308 Comm: rmmod Not tainted 6.1.0-rc4-next-20221111+ #131 >> RIP: 0010:kernfs_remove_by_name_ns+0xdd/0x100 >> RSP: 0018:ffff88812149fbc8 EFLAGS: 00010282 >> RAX: 0000000000000000 RBX: ffffffffb8137508 RCX: 0000000000000000 >> RDX: 0000000000000001 RSI: ffffffffb6b49ae0 RDI: ffffed1024293f6b >> RBP: ffffffffb8137600 R08: 0000000000000001 R09: ffffed1024293f3d >> R10: ffff88812149f9e7 R11: ffffed1024293f3c R12: 0000000000000000 >> R13: ffffffffb6b2d2a0 R14: ffffffffb6b2d1e0 R15: ffff88822f7f14b8 >> FS: 00007f97eacb9740(0000) GS:ffff8883ace00000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f97e9b72b81 CR3: 000000022fbda000 CR4: 00000000000006e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> <TASK> >> remove_files.isra.0+0x6c/0x170 >> sysfs_remove_group+0x9b/0x180 >> sysfs_remove_groups+0x4f/0xa0 >> __kobject_del+0x7d/0x1d0 >> kobject_del+0x32/0x50 >> blk_mq_sysfs_unregister.cold+0x8/0xd >> blk_unregister_queue+0xed/0x260 >> del_gendisk+0x27e/0x900 >> null_del_dev.part.0+0x166/0x510 [null_blk] >> null_destroy_dev+0x37/0x5c [null_blk] >> null_exit+0x4c/0x9d [null_blk] >> __do_sys_delete_module.isra.0+0x2f3/0x520 >> do_syscall_64+0x3b/0x90 >> entry_SYSCALL_64_after_hwframe+0x72/0xdc >> </TASK> >> >> Fault injection context as follows: >> kobject_add >> blk_mq_register_hctx >> blk_mq_sysfs_register >> blk_register_queue >> device_add_disk >> null_add_dev.part.0 [null_blk] >> >> As 'blk_mq_sysfs_register' may failed, but when unregister mq sysfs don't >> judge sysfs if registered. 'blk_mq_sysfs_register' also didn't handle >> error correctly. >> To solve above issue, if sysfs is unregstered just exit. >> >> Signed-off-by: Ye Bin <yebin10@huawei.com> >> --- >> block/blk-mq-sysfs.c | 13 +++++++++++-- >> 1 file changed, 11 insertions(+), 2 deletions(-) >> >> diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c >> index 93997d297d42..0cda0a729f3c 100644 >> --- a/block/blk-mq-sysfs.c >> +++ b/block/blk-mq-sysfs.c >> @@ -185,7 +185,7 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx) >> { >> struct request_queue *q = hctx->queue; >> struct blk_mq_ctx *ctx; >> - int i, ret; >> + int i, j, ret; >> >> if (!hctx->nr_ctx) >> return 0; >> @@ -197,9 +197,16 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx) >> hctx_for_each_ctx(hctx, ctx, i) { >> ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu); >> if (ret) >> - break; >> + goto out; >> } >> >> + return 0; >> +out: >> + hctx_for_each_ctx(hctx, ctx, j) { >> + if (j < i) >> + kobject_del(&ctx->kobj); >> + } >> + kobject_del(&hctx->kobj); > The above change looks fine. I will send v2 patch for this part. >> return ret; >> } >> >> @@ -278,6 +285,8 @@ void blk_mq_sysfs_unregister(struct gendisk *disk) >> struct blk_mq_hw_ctx *hctx; >> unsigned long i; >> >> + if (!q->mq_sysfs_init_done) >> + return; > The above should be one warning, and I suggest to handle failure of blk_mq_sysfs_register > from blk_register_queue() in this patch too. > > Thanks, > Ming > > . I think "[PATCH 3/5] block: fix error unwinding in blk_register_queue" already do what your suggest.
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