From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id E9F0E4405BD for ; Thu, 16 Feb 2017 00:22:21 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id 65so11093954pgi.7 for ; Wed, 15 Feb 2017 21:22:21 -0800 (PST) Received: from lgeamrelo12.lge.com (LGEAMRELO12.lge.com. [156.147.23.52]) by mx.google.com with ESMTP id c12si5904634pfe.23.2017.02.15.21.22.20 for ; Wed, 15 Feb 2017 21:22:21 -0800 (PST) Date: Thu, 16 Feb 2017 14:22:18 +0900 From: Minchan Kim Subject: swap_cluster_info lockdep splat Message-ID: <20170216052218.GA13908@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: "Huang, Ying" Cc: Andrew Morton , Tim Chen , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org Hi Huang, With changing from bit lock to spinlock of swap_cluster_info, my zram test failed with below message. It seems nested lock problem so need to play with lockdep. Thanks. ============================================= [ INFO: possible recursive locking detected ] 4.10.0-rc8-next-20170214-zram #24 Not tainted --------------------------------------------- as/6557 is trying to acquire lock: (&(&((cluster_info + ci)->lock))->rlock){+.+.-.}, at: [] cluster_list_add_tail.part.31+0x33/0x70 but task is already holding lock: (&(&((cluster_info + ci)->lock))->rlock){+.+.-.}, at: [] swapcache_free_entries+0x9b/0x330 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&((cluster_info + ci)->lock))->rlock); lock(&(&((cluster_info + ci)->lock))->rlock); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by as/6557: #0: (&(&cache->free_lock)->rlock){......}, at: [] free_swap_slot+0x8b/0x110 #1: (&(&p->lock)->rlock){+.+.-.}, at: [] swapcache_free_entries+0x75/0x330 #2: (&(&((cluster_info + ci)->lock))->rlock){+.+.-.}, at: [] swapcache_free_entries+0x9b/0x330 stack backtrace: CPU: 3 PID: 6557 Comm: as Not tainted 4.10.0-rc8-next-20170214-zram #24 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x85/0xc2 __lock_acquire+0x15ea/0x1640 lock_acquire+0x100/0x1f0 ? cluster_list_add_tail.part.31+0x33/0x70 _raw_spin_lock+0x38/0x50 ? cluster_list_add_tail.part.31+0x33/0x70 cluster_list_add_tail.part.31+0x33/0x70 swapcache_free_entries+0x2f9/0x330 free_swap_slot+0xf8/0x110 swapcache_free+0x36/0x40 delete_from_swap_cache+0x5f/0xa0 try_to_free_swap+0x6e/0xa0 free_pages_and_swap_cache+0x7d/0xb0 tlb_flush_mmu_free+0x36/0x60 tlb_finish_mmu+0x1c/0x50 exit_mmap+0xc7/0x150 mmput+0x51/0x110 do_exit+0x2b2/0xc30 ? trace_hardirqs_on_caller+0x129/0x1b0 do_group_exit+0x50/0xd0 SyS_exit_group+0x14/0x20 entry_SYSCALL_64_fastpath+0x23/0xc6 RIP: 0033:0x2b9a2dbdf309 RSP: 002b:00007ffe71887528 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00002b9a2dbdf309 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00002b9a2ded8858 R08: 000000000000003c R09: 00000000000000e7 R10: ffffffffffffff60 R11: 0000000000000246 R12: 00002b9a2ded8858 R13: 00002b9a2dedde80 R14: 000000000255f770 R15: 0000000000000001 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org