From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= Subject: Re: fuzz testing an ext4fs file system under a 32 bit Linux user mode linux guest let task jbd2/ubda hang Date: Sat, 09 Aug 2014 20:45:43 +0200 Message-ID: <53E66C57.8010303@gmx.de> References: <53DE3E92.3060304@gmx.de> <20140803184210.GV24826@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-ext4@vger.kernel.org, UML devel To: Theodore Ts'o Return-path: Received: from mout.gmx.net ([212.227.15.18]:57364 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751983AbaHISps (ORCPT ); Sat, 9 Aug 2014 14:45:48 -0400 In-Reply-To: <20140803184210.GV24826@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 08/03/2014 08:42 PM, Theodore Ts'o wrote: > On Sun, Aug 03, 2014 at 03:52:18PM +0200, Toralf F=C3=B6rster wrote: >> Hello, >> >> fuzzying a 32 bit stable Gentoo x86 linux with trinity (and without = excluding the munmap syscall but it might be independed from this) give= s within a 32 bit user mode linux guest : >=20 > The problem with these sorts of trinity bug reports is that we have n= o > idea which syscall or set of syscalls might have corrupted kernel > state to the point where the kernel started malfunctioning. >=20 > Sometimes, a trinity induced bug is obvious, when it causes a system > call to immediately access an illegal memory location. But if it > causes some more subtle corruption, possibly in a completely unrelate= d > subsystem, figuring out what actually happened can be close to > impossible. >=20 > So there's not much I can do with this sort of bug report. If you ca= n > easily repeat it, and you can dump out the system call stream, we > might be able to make a smaller reproduction case, at which point > trying to debug this sort of failure would be tractable. >=20 > Cheers, >=20 > - Ted >=20 ok, fair enough. BTW may I just ask, if the following (same 32 bit system, host and UML = guest are both at v3.16, 4 trinity childs hammering victims files in a = ramdisk within the uML guest) matches the above too ? Or does the BUG o= utput here more helpful data ? : Kernel panic - not syncing: BUG! CPU: 0 PID: 105 Comm: kworker/u2:2 Not tainted 3.16.0 #2 Workqueue: writeback bdi_writeback_workfn (flush-98:0) Stack: 085be12e 085be12e 00000003 086e8547 0000000c 000002b3 85177cc4 85177c7= 4 085015c3 00000000 85177c48 85177c9c 084fd6dd 085c9dc0 08727180 085bae4= a 85177ca8 00000000 0000000c 000002b3 85177cc4 85177d10 0818ec0f 085bae4= a Call Trace: [<085015c3>] dump_stack+0x26/0x28 [<084fd6dd>] panic+0x8f/0x1a9 [<0818ec0f>] mpage_release_unused_pages+0x11f/0x1b0 [<0819395a>] ext4_writepages+0x42a/0x640 [<080d87e5>] do_writepages+0x25/0x50 [<0812fd2c>] __writeback_single_inode+0x3c/0xf0 [<08130064>] writeback_sb_inodes+0x1d4/0x320 [<08130214>] __writeback_inodes_wb+0x64/0xa0 [<08130501>] wb_writeback+0xf1/0x190 [<081308a2>] bdi_writeback_workfn+0xa2/0x2d0 [<08504c56>] ? _raw_spin_unlock_irq+0x16/0x20 [<0809e30c>] ? finish_task_switch.constprop.52+0x3c/0x90 [<08091474>] process_one_work+0x184/0x2f0 [<080918da>] worker_thread+0x2fa/0x540 [<08504c3c>] ? _raw_spin_unlock_irqrestore+0x1c/0x20 [<08502d65>] ? schedule+0x55/0x60 [<080915e0>] ? worker_thread+0x0/0x540 [<080971b6>] kthread+0xd6/0xe0 [<0805f68b>] new_thread_handler+0x6b/0x90 --=20 Toralf -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1XGBeO-00085K-Fj for user-mode-linux-devel@lists.sourceforge.net; Sat, 09 Aug 2014 18:45:56 +0000 Received: from mout.gmx.net ([212.227.15.18]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1XGBeN-0003z9-01 for user-mode-linux-devel@lists.sourceforge.net; Sat, 09 Aug 2014 18:45:56 +0000 Message-ID: <53E66C57.8010303@gmx.de> Date: Sat, 09 Aug 2014 20:45:43 +0200 From: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= MIME-Version: 1.0 References: <53DE3E92.3060304@gmx.de> <20140803184210.GV24826@thunk.org> In-Reply-To: <20140803184210.GV24826@thunk.org> List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net Subject: Re: [uml-devel] fuzz testing an ext4fs file system under a 32 bit Linux user mode linux guest let task jbd2/ubda hang To: Theodore Ts'o Cc: linux-ext4@vger.kernel.org, UML devel T24gMDgvMDMvMjAxNCAwODo0MiBQTSwgVGhlb2RvcmUgVHMnbyB3cm90ZToKPiBPbiBTdW4sIEF1 ZyAwMywgMjAxNCBhdCAwMzo1MjoxOFBNICswMjAwLCBUb3JhbGYgRsO2cnN0ZXIgd3JvdGU6Cj4+ IEhlbGxvLAo+Pgo+PiBmdXp6eWluZyBhIDMyIGJpdCBzdGFibGUgR2VudG9vIHg4NiBsaW51eCB3 aXRoIHRyaW5pdHkgKGFuZCB3aXRob3V0IGV4Y2x1ZGluZyB0aGUgbXVubWFwIHN5c2NhbGwgYnV0 IGl0IG1pZ2h0IGJlIGluZGVwZW5kZWQgZnJvbSB0aGlzKSBnaXZlcyB3aXRoaW4gYSAzMiBiaXQg dXNlciBtb2RlIGxpbnV4IGd1ZXN0IDoKPiAKPiBUaGUgcHJvYmxlbSB3aXRoIHRoZXNlIHNvcnRz IG9mIHRyaW5pdHkgYnVnIHJlcG9ydHMgaXMgdGhhdCB3ZSBoYXZlIG5vCj4gaWRlYSB3aGljaCBz eXNjYWxsIG9yIHNldCBvZiBzeXNjYWxscyBtaWdodCBoYXZlIGNvcnJ1cHRlZCBrZXJuZWwKPiBz dGF0ZSB0byB0aGUgcG9pbnQgd2hlcmUgdGhlIGtlcm5lbCBzdGFydGVkIG1hbGZ1bmN0aW9uaW5n Lgo+IAo+IFNvbWV0aW1lcywgYSB0cmluaXR5IGluZHVjZWQgYnVnIGlzIG9idmlvdXMsIHdoZW4g aXQgY2F1c2VzIGEgc3lzdGVtCj4gY2FsbCB0byBpbW1lZGlhdGVseSBhY2Nlc3MgYW4gaWxsZWdh bCBtZW1vcnkgbG9jYXRpb24uICBCdXQgaWYgaXQKPiBjYXVzZXMgc29tZSBtb3JlIHN1YnRsZSBj b3JydXB0aW9uLCBwb3NzaWJseSBpbiBhIGNvbXBsZXRlbHkgdW5yZWxhdGVkCj4gc3Vic3lzdGVt LCBmaWd1cmluZyBvdXQgd2hhdCBhY3R1YWxseSBoYXBwZW5lZCBjYW4gYmUgY2xvc2UgdG8KPiBp bXBvc3NpYmxlLgo+IAo+IFNvIHRoZXJlJ3Mgbm90IG11Y2ggSSBjYW4gZG8gd2l0aCB0aGlzIHNv cnQgb2YgYnVnIHJlcG9ydC4gIElmIHlvdSBjYW4KPiBlYXNpbHkgcmVwZWF0IGl0LCBhbmQgeW91 IGNhbiBkdW1wIG91dCB0aGUgc3lzdGVtIGNhbGwgc3RyZWFtLCB3ZQo+IG1pZ2h0IGJlIGFibGUg dG8gbWFrZSBhIHNtYWxsZXIgcmVwcm9kdWN0aW9uIGNhc2UsIGF0IHdoaWNoIHBvaW50Cj4gdHJ5 aW5nIHRvIGRlYnVnIHRoaXMgc29ydCBvZiBmYWlsdXJlIHdvdWxkIGJlIHRyYWN0YWJsZS4KPiAK PiBDaGVlcnMsCj4gCj4gCQkJCQkJLSBUZWQKPiAKb2ssIGZhaXIgZW5vdWdoLgoKCkJUVyBtYXkg SSBqdXN0IGFzaywgaWYgdGhlIGZvbGxvd2luZyAoc2FtZSAzMiBiaXQgc3lzdGVtLCBob3N0IGFu ZCBVTUwgZ3Vlc3QgYXJlIGJvdGggYXQgdjMuMTYsIDQgdHJpbml0eSBjaGlsZHMgaGFtbWVyaW5n IHZpY3RpbXMgZmlsZXMgaW4gYSByYW1kaXNrIHdpdGhpbiB0aGUgdU1MIGd1ZXN0KSBtYXRjaGVz IHRoZSBhYm92ZSB0b28gPyBPciBkb2VzIHRoZSBCVUcgb3V0cHV0IGhlcmUgbW9yZSBoZWxwZnVs IGRhdGEgPyA6CgoKS2VybmVsIHBhbmljIC0gbm90IHN5bmNpbmc6IEJVRyEKQ1BVOiAwIFBJRDog MTA1IENvbW06IGt3b3JrZXIvdTI6MiBOb3QgdGFpbnRlZCAzLjE2LjAgIzIKV29ya3F1ZXVlOiB3 cml0ZWJhY2sgYmRpX3dyaXRlYmFja193b3JrZm4gKGZsdXNoLTk4OjApClN0YWNrOgogMDg1YmUx MmUgMDg1YmUxMmUgMDAwMDAwMDMgMDg2ZTg1NDcgMDAwMDAwMGMgMDAwMDAyYjMgODUxNzdjYzQg ODUxNzdjNzQKIDA4NTAxNWMzIDAwMDAwMDAwIDg1MTc3YzQ4IDg1MTc3YzljIDA4NGZkNmRkIDA4 NWM5ZGMwIDA4NzI3MTgwIDA4NWJhZTRhCiA4NTE3N2NhOCAwMDAwMDAwMCAwMDAwMDAwYyAwMDAw MDJiMyA4NTE3N2NjNCA4NTE3N2QxMCAwODE4ZWMwZiAwODViYWU0YQpDYWxsIFRyYWNlOgogWzww ODUwMTVjMz5dIGR1bXBfc3RhY2srMHgyNi8weDI4CiBbPDA4NGZkNmRkPl0gcGFuaWMrMHg4Zi8w eDFhOQogWzwwODE4ZWMwZj5dIG1wYWdlX3JlbGVhc2VfdW51c2VkX3BhZ2VzKzB4MTFmLzB4MWIw CiBbPDA4MTkzOTVhPl0gZXh0NF93cml0ZXBhZ2VzKzB4NDJhLzB4NjQwCiBbPDA4MGQ4N2U1Pl0g ZG9fd3JpdGVwYWdlcysweDI1LzB4NTAKIFs8MDgxMmZkMmM+XSBfX3dyaXRlYmFja19zaW5nbGVf aW5vZGUrMHgzYy8weGYwCiBbPDA4MTMwMDY0Pl0gd3JpdGViYWNrX3NiX2lub2RlcysweDFkNC8w eDMyMAogWzwwODEzMDIxND5dIF9fd3JpdGViYWNrX2lub2Rlc193YisweDY0LzB4YTAKIFs8MDgx MzA1MDE+XSB3Yl93cml0ZWJhY2srMHhmMS8weDE5MAogWzwwODEzMDhhMj5dIGJkaV93cml0ZWJh Y2tfd29ya2ZuKzB4YTIvMHgyZDAKIFs8MDg1MDRjNTY+XSA/IF9yYXdfc3Bpbl91bmxvY2tfaXJx KzB4MTYvMHgyMAogWzwwODA5ZTMwYz5dID8gZmluaXNoX3Rhc2tfc3dpdGNoLmNvbnN0cHJvcC41 MisweDNjLzB4OTAKIFs8MDgwOTE0NzQ+XSBwcm9jZXNzX29uZV93b3JrKzB4MTg0LzB4MmYwCiBb PDA4MDkxOGRhPl0gd29ya2VyX3RocmVhZCsweDJmYS8weDU0MAogWzwwODUwNGMzYz5dID8gX3Jh d19zcGluX3VubG9ja19pcnFyZXN0b3JlKzB4MWMvMHgyMAogWzwwODUwMmQ2NT5dID8gc2NoZWR1 bGUrMHg1NS8weDYwCiBbPDA4MDkxNWUwPl0gPyB3b3JrZXJfdGhyZWFkKzB4MC8weDU0MAogWzww ODA5NzFiNj5dIGt0aHJlYWQrMHhkNi8weGUwCiBbPDA4MDVmNjhiPl0gbmV3X3RocmVhZF9oYW5k bGVyKzB4NmIvMHg5MAoKCgotLSAKVG9yYWxmCgoKLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tCl9fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fClVzZXItbW9kZS1saW51 eC1kZXZlbCBtYWlsaW5nIGxpc3QKVXNlci1tb2RlLWxpbnV4LWRldmVsQGxpc3RzLnNvdXJjZWZv cmdlLm5ldApodHRwczovL2xpc3RzLnNvdXJjZWZvcmdlLm5ldC9saXN0cy9saXN0aW5mby91c2Vy LW1vZGUtbGludXgtZGV2ZWwK