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[2001:44b8:1113:6700:b05d:cbfe:b2ee:de17]) by smtp.gmail.com with ESMTPSA id d14sm15023364pfq.117.2019.12.20.11.27.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Dec 2019 11:27:56 -0800 (PST) From: Daniel Axtens To: Brian Foster Cc: syzbot , akpm@linux-foundation.org, allison.henderson@oracle.com, aryabinin@virtuozzo.com, darrick.wong@oracle.com, dchinner@redhat.com, dvyukov@google.com, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, sandeen@redhat.com, syzkaller-bugs@googlegroups.com, torvalds@linux-foundation.org Subject: Re: BUG: unable to handle kernel paging request in xfs_sb_quiet_read_verify In-Reply-To: <20191220130441.GA11941@bfoster> References: <000000000000d99340059a100686@google.com> <874kxvttx0.fsf@dja-thinkpad.axtens.net> <20191220130441.GA11941@bfoster> Date: Sat, 21 Dec 2019 06:27:51 +1100 Message-ID: <87zhfmssp4.fsf@dja-thinkpad.axtens.net> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org >> > HEAD commit: 2187f215 Merge tag 'for-5.5-rc2-tag' of git://git.kernel.o.. > Since this mapping functionality is fairly fundamental code in XFS, I > ran a quick test to use a multi-page directory block size (i.e. mkfs.xfs > -f -nsize=8k), started populating a directory and very quickly hit > a similar crash. I'm going to double check that this works as expected > without KASAN vmalloc support enabled, but is it possible something is > wrong with KASAN here? Yes, as it turns out. xfs is using vm_map_ram, and the commit syzkaller is testing is missing the support for vm_map_ram. Support landed in master at d98c9e83b5e7 ("kasan: fix crashes on access to memory mapped by vm_map_ram()") but that's _after_ 2187f215 which syzkaller was testing #syz fix: kasan: fix crashes on access to memory mapped by vm_map_ram() Sorry for the noise. Regards, Daniel > > Brian > >> Regards, >> Daniel >> >> > >> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=161240aee00000 >> > final crash: https://syzkaller.appspot.com/x/report.txt?x=151240aee00000 >> > console output: https://syzkaller.appspot.com/x/log.txt?x=111240aee00000 >> > >> > IMPORTANT: if you fix the bug, please add the following tag to the commit: >> > Reported-by: syzbot+4722bf4c6393b73a792b@syzkaller.appspotmail.com >> > Fixes: 0609ae011deb ("x86/kasan: support KASAN_VMALLOC") >> > >> > BUG: unable to handle page fault for address: fffff52000680000 >> > #PF: supervisor read access in kernel mode >> > #PF: error_code(0x0000) - not-present page >> > PGD 21ffee067 P4D 21ffee067 PUD aa51c067 PMD a85e1067 PTE 0 >> > Oops: 0000 [#1] PREEMPT SMP KASAN >> > CPU: 1 PID: 3088 Comm: kworker/1:2 Not tainted 5.5.0-rc2-syzkaller #0 >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> > Google 01/01/2011 >> > Workqueue: xfs-buf/loop0 xfs_buf_ioend_work >> > RIP: 0010:xfs_sb_quiet_read_verify+0x47/0xc0 fs/xfs/libxfs/xfs_sb.c:735 >> > Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 7f 49 8b 9c 24 30 01 >> > 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 04 02 84 >> > c0 74 04 3c 03 7e 50 8b 1b bf 58 46 53 42 89 de e8 >> > RSP: 0018:ffffc90008187cc0 EFLAGS: 00010a06 >> > RAX: dffffc0000000000 RBX: ffffc90003400000 RCX: ffffffff82ad3c26 >> > RDX: 1ffff92000680000 RSI: ffffffff82aa0a0f RDI: ffff8880a2cdba70 >> > RBP: ffffc90008187cd0 R08: ffff88809eb6c500 R09: ffffed1015d2703d >> > R10: ffffed1015d2703c R11: ffff8880ae9381e3 R12: ffff8880a2cdb940 >> > R13: ffff8880a2cdb95c R14: ffff8880a2cdbb74 R15: 0000000000000000 >> > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 >> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> > CR2: fffff52000680000 CR3: 000000009f5ab000 CR4: 00000000001406e0 >> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> > Call Trace: >> > xfs_buf_ioend+0x3f9/0xde0 fs/xfs/xfs_buf.c:1162 >> > xfs_buf_ioend_work+0x19/0x20 fs/xfs/xfs_buf.c:1183 >> > process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 >> > worker_thread+0x98/0xe40 kernel/workqueue.c:2410 >> > kthread+0x361/0x430 kernel/kthread.c:255 >> > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 >> > Modules linked in: >> > CR2: fffff52000680000 >> > ---[ end trace 744ceb50d377bf94 ]--- >> > RIP: 0010:xfs_sb_quiet_read_verify+0x47/0xc0 fs/xfs/libxfs/xfs_sb.c:735 >> > Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 7f 49 8b 9c 24 30 01 >> > 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 04 02 84 >> > c0 74 04 3c 03 7e 50 8b 1b bf 58 46 53 42 89 de e8 >> > RSP: 0018:ffffc90008187cc0 EFLAGS: 00010a06 >> > RAX: dffffc0000000000 RBX: ffffc90003400000 RCX: ffffffff82ad3c26 >> > RDX: 1ffff92000680000 RSI: ffffffff82aa0a0f RDI: ffff8880a2cdba70 >> > RBP: ffffc90008187cd0 R08: ffff88809eb6c500 R09: ffffed1015d2703d >> > R10: ffffed1015d2703c R11: ffff8880ae9381e3 R12: ffff8880a2cdb940 >> > R13: ffff8880a2cdb95c R14: ffff8880a2cdbb74 R15: 0000000000000000 >> > FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 >> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> > CR2: fffff52000680000 CR3: 000000009f5ab000 CR4: 00000000001406e0 >> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> > >> > >> > --- >> > This bug is generated by a bot. It may contain errors. >> > See https://goo.gl/tpsmEJ for more information about syzbot. >> > syzbot engineers can be reached at syzkaller@googlegroups.com. >> > >> > syzbot will keep track of this bug report. See: >> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. >> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection >> > syzbot can test patches for this bug, for details see: >> > https://goo.gl/tpsmEJ#testing-patches >>