From: Dan Williams Subject: Re: [PATCH v6 4/7] dax: add support for fsync/msync Date: Sun, 3 Jan 2016 10:13:06 -0800 Message-ID: References: <1450899560-26708-1-git-send-email-ross.zwisler@linux.intel.com> <1450899560-26708-5-git-send-email-ross.zwisler@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: "linux-kernel@vger.kernel.org" , "H. Peter Anvin" , "J. Bruce Fields" , "Theodore Ts'o" , Alexander Viro , Andreas Dilger , Dave Chinner , Ingo Molnar , Jan Kara , Jeff Layton , Matthew Wilcox , Thomas Gleixner , linux-ext4 , linux-fsdevel , Linux MM , "linux-nvdimm@lists.01.org" , X86 ML , XFS Developers , Andrew Morton , Matthew Wilcox , Dave Hansen To: Ross Zwisler Return-path: In-Reply-To: <1450899560-26708-5-git-send-email-ross.zwisler@linux.intel.com> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org On Wed, Dec 23, 2015 at 11:39 AM, Ross Zwisler wrote: > To properly handle fsync/msync in an efficient way DAX needs to track dirty > pages so it is able to flush them durably to media on demand. > > The tracking of dirty pages is done via the radix tree in struct > address_space. This radix tree is already used by the page writeback > infrastructure for tracking dirty pages associated with an open file, and > it already has support for exceptional (non struct page*) entries. We > build upon these features to add exceptional entries to the radix tree for > DAX dirty PMD or PTE pages at fault time. > > Signed-off-by: Ross Zwisler I'm hitting the following report with the ndctl dax test [1] on next-20151231. I bisected it to commit 3cb108f941de "dax-add-support-for-fsync-sync-v6". I'll take a closer look tomorrow, but in case someone can beat me to it, here's the back-trace: ------------[ cut here ]------------ kernel BUG at fs/inode.c:497! [..] CPU: 1 PID: 3001 Comm: umount Tainted: G O 4.4.0-rc7+ #2412 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8800da2a5a00 ti: ffff880307794000 task.ti: ffff880307794000 RIP: 0010:[] [] clear_inode+0x71/0x80 RSP: 0018:ffff880307797d50 EFLAGS: 00010002 RAX: ffff8800da2a5a00 RBX: ffff8800ca2e7328 RCX: ffff8800da2a5a28 RDX: 0000000000000001 RSI: 0000000000000005 RDI: ffff8800ca2e7530 RBP: ffff880307797d60 R08: ffffffff82900ae0 R09: 0000000000000000 R10: ffff8800ca2e7548 R11: 0000000000000000 R12: ffff8800ca2e7530 R13: ffff8800ca2e7328 R14: ffff8800da2e88d0 R15: ffff8800da2e88d0 FS: 00007f2b22f4a880(0000) GS:ffff88031fc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005648abd933e8 CR3: 000000007f3fc000 CR4: 00000000000006e0 Stack: ffff8800ca2e7328 ffff8800ca2e7000 ffff880307797d88 ffffffffa01c18af ffff8800ca2e7328 ffff8800ca2e74d0 ffffffffa01ec740 ffff880307797db0 ffffffff81281038 ffff8800ca2e74c0 ffff880307797e00 ffff8800ca2e7328 Call Trace: [] xfs_fs_evict_inode+0x5f/0x110 [xfs] [] evict+0xb8/0x180 [] dispose_list+0x3b/0x50 [] evict_inodes+0x144/0x170 [] generic_shutdown_super+0x3f/0xf0 [] kill_block_super+0x27/0x70 [] deactivate_locked_super+0x43/0x70 [] deactivate_super+0x5c/0x60 [] cleanup_mnt+0x3f/0x90 [] __cleanup_mnt+0x12/0x20 [] task_work_run+0x76/0x90 [] syscall_return_slowpath+0x20a/0x280 [] int_ret_from_sys_call+0x25/0x9f Code: 48 8d 93 30 03 00 00 48 39 c2 75 23 48 8b 83 d0 00 00 00 a8 20 74 1a a8 40 75 18 48 c7 8 3 d0 00 00 00 60 00 00 00 5b 41 5c 5d c3 <0f> 0b 0f 0b 0f 0b 0f 0b 0f 0b 0f 1f 44 00 00 0f 1f 44 00 00 55 RIP [] clear_inode+0x71/0x80 RSP ---[ end trace 3b1d8898a94a4fc1 ]--- [1]: git://git@github.com:pmem/ndctl.git pending make TESTS="test/dax.sh" check -- 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