From: Justin He <Justin.He@arm.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Jonathan Corbet <corbet@lwn.net>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ira Weiny <ira.weiny@intel.com>,
Eric Biggers <ebiggers@google.com>,
"Ahmed S. Darwish" <a.darwish@linutronix.de>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: RE: [PATCH 13/14] d_path: prepend_path() is unlikely to return non-zero
Date: Mon, 28 Jun 2021 03:28:19 +0000 [thread overview]
Message-ID: <AM6PR08MB43769E57C213CD2C92476F2CF7039@AM6PR08MB4376.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <YNYZTIP+anazsz/U@zeniv-ca.linux.org.uk>
Hi Al
> -----Original Message-----
> From: Al Viro <viro@ftp.linux.org.uk> On Behalf Of Al Viro
> Sent: Saturday, June 26, 2021 1:59 AM
> To: Justin He <Justin.He@arm.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>; Petr Mladek
> <pmladek@suse.com>; Steven Rostedt <rostedt@goodmis.org>; Sergey
> Senozhatsky <senozhatsky@chromium.org>; Andy Shevchenko
> <andriy.shevchenko@linux.intel.com>; Rasmus Villemoes
> <linux@rasmusvillemoes.dk>; Jonathan Corbet <corbet@lwn.net>; Heiko
> Carstens <hca@linux.ibm.com>; Vasily Gorbik <gor@linux.ibm.com>; Christian
> Borntraeger <borntraeger@de.ibm.com>; Eric W . Biederman
> <ebiederm@xmission.com>; Darrick J. Wong <darrick.wong@oracle.com>; Peter
> Zijlstra (Intel) <peterz@infradead.org>; Ira Weiny <ira.weiny@intel.com>;
> Eric Biggers <ebiggers@google.com>; Ahmed S. Darwish
> <a.darwish@linutronix.de>; open list:DOCUMENTATION <linux-
> doc@vger.kernel.org>; Linux Kernel Mailing List <linux-
> kernel@vger.kernel.org>; linux-s390 <linux-s390@vger.kernel.org>; linux-
> fsdevel <linux-fsdevel@vger.kernel.org>
> Subject: Re: [PATCH 13/14] d_path: prepend_path() is unlikely to return
> non-zero
>
> On Fri, Jun 25, 2021 at 08:00:49AM +0000, Justin He wrote:
> > --- a/fs/d_path.c
> > +++ b/fs/d_path.c
> > @@ -210,6 +210,7 @@ static int prepend_path(const struct path *path,
> > b = *p;
> > read_seqbegin_or_lock(&rename_lock, &seq);
> > error = __prepend_path(path->dentry, real_mount(path->mnt), root,
> &b);
> > + printk("prepend=%d",error);
> > if (!(seq & 1))
> > rcu_read_unlock();
> > if (need_seqretry(&rename_lock, seq)) {
> >
> > Then the result seems a little different:
> > root@entos-ampere-02:~# dmesg |grep prepend=1 |wc -l
> > 7417
> > root@entos-ampere-02:~# dmesg |grep prepend=0 |wc -l
> > 772
> >
> > The kernel is 5.13.0-rc2+ + this series + my '%pD' series
> >
> > Any thoughts?
>
> On which loads? 1 here is "mount/dentry pair is in somebody
> else's namespace or outside of the subtree we are chrooted
> into". IOW, what's calling d_path() on your setup?
No special loads, merely collecting the results after kernel boots up.
To narrow down, I tested your branch [1] *without* my '%pD' series:
[1] https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git/log/?h=work.d_path
The result is the same after kernel boots up.
The call trace are as follows:
The prepend_path returns 1:
Call trace:
prepend_path+0x144/0x340
d_absolute_path+0x6c/0xb8
aa_path_name+0x1c0/0x3d8
profile_transition+0x90/0x908
apparmor_bprm_creds_for_exec+0x914/0xaf0
security_bprm_creds_for_exec+0x34/0x50
bprm_execve+0x178/0x668
do_execveat_common.isra.47+0x1b4/0x1c8
__arm64_sys_execve+0x44/0x58
invoke_syscall+0x54/0x110
el0_svc_common.constprop.2+0x5c/0xe0
do_el0_svc+0x34/0xa0
el0_svc+0x20/0x30
el0_sync_handler+0x88/0xb0
el0_sync+0x148/0x180
The prepend_path returns 0:
Call trace:
prepend_path+0x144/0x340
d_path+0x110/0x158
proc_pid_readlink+0xbc/0x1b8
vfs_readlink+0x14c/0x170
do_readlinkat+0x134/0x168
__arm64_sys_readlinkat+0x28/0x38
invoke_syscall+0x54/0x110
el0_svc_common.constprop.2+0x5c/0xe0
do_el0_svc+0x34/0xa0
el0_svc+0x20/0x30
el0_sync_handler+0x88/0xb0
el0_sync+0x148/0x180
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next prev parent reply other threads:[~2021-06-28 3:28 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 12:25 [PATCH RFC 0/3] make '%pD' print full path for file Jia He
2021-05-08 12:25 ` [PATCH RFC 1/3] fs: introduce helper d_path_fast() Jia He
2021-05-08 15:30 ` Linus Torvalds
2021-05-08 19:13 ` Al Viro
2021-05-08 20:39 ` Linus Torvalds
2021-05-08 21:05 ` Al Viro
2021-05-08 22:17 ` Linus Torvalds
2021-05-08 22:46 ` Al Viro
2021-05-08 22:48 ` Linus Torvalds
2021-05-08 23:15 ` Al Viro
2021-05-08 23:18 ` Al Viro
2021-05-09 22:58 ` Eric W. Biederman
2021-05-10 12:51 ` Christian Brauner
2021-05-10 7:20 ` Christian Brauner
2021-05-08 22:42 ` Linus Torvalds
2021-05-08 22:47 ` Linus Torvalds
2021-05-09 2:28 ` Al Viro
2021-05-09 2:53 ` Linus Torvalds
2021-05-19 0:43 ` [PATCHSET] d_path cleanups Al Viro
2021-05-19 0:48 ` [PATCH 01/14] d_path: "\0" is {0,0}, not {0} Al Viro
2021-05-19 0:48 ` [PATCH 02/14] d_path: saner calling conventions for __dentry_path() Al Viro
2021-06-25 9:32 ` Justin He
2021-07-07 4:52 ` Justin He
2021-05-19 0:48 ` [PATCH 03/14] d_path: regularize handling of root dentry in __dentry_path() Al Viro
2021-07-07 4:50 ` Justin He
2021-05-19 0:48 ` [PATCH 04/14] d_path: get rid of path_with_deleted() Al Viro
2021-05-19 0:48 ` [PATCH 05/14] getcwd(2): saner logics around prepend_path() call Al Viro
2021-07-07 7:41 ` Justin He
2021-05-19 0:48 ` [PATCH 06/14] d_path: don't bother with return value of prepend() Al Viro
2021-06-24 6:13 ` Justin He
2021-05-19 0:48 ` [PATCH 07/14] d_path: lift -ENAMETOOLONG handling into callers of prepend_path() Al Viro
2021-06-25 9:18 ` Justin He
2021-06-28 5:20 ` Justin He
2021-05-19 0:48 ` [PATCH 08/14] d_path: make prepend_name() boolean Al Viro
2021-05-20 9:12 ` Justin He
2021-05-20 9:19 ` Andy Shevchenko
2021-05-20 14:53 ` Petr Mladek
2021-05-20 19:35 ` Al Viro
2021-07-07 7:43 ` Justin He
2021-05-19 0:48 ` [PATCH 09/14] d_path: introduce struct prepend_buffer Al Viro
2021-06-23 13:28 ` Justin He
2021-06-24 9:29 ` Enrico Weigelt, metux IT consult
2021-06-25 0:43 ` Justin He
2021-06-28 16:42 ` Enrico Weigelt, metux IT consult
2021-06-28 17:10 ` Andy Shevchenko
2021-05-19 0:48 ` [PATCH 10/14] d_path: prepend_path(): get rid of vfsmnt Al Viro
2021-05-19 0:48 ` [PATCH 11/14] d_path: prepend_path(): lift resetting b in case when we'd return 3 out of loop Al Viro
2021-05-19 0:48 ` [PATCH 12/14] d_path: prepend_path(): lift the inner loop into a new helper Al Viro
2021-05-19 8:07 ` Andy Shevchenko
2021-05-19 15:55 ` Al Viro
2021-07-07 7:52 ` Justin He
2021-05-19 0:49 ` [PATCH 13/14] d_path: prepend_path() is unlikely to return non-zero Al Viro
2021-06-25 8:00 ` Justin He
2021-06-25 17:58 ` Al Viro
2021-06-28 3:28 ` Justin He [this message]
2021-06-28 4:14 ` Al Viro
2021-06-28 4:36 ` Justin He
2021-06-28 4:37 ` Justin He
2021-05-19 0:49 ` [PATCH 14/14] getcwd(2): clean up error handling Al Viro
2021-07-07 8:03 ` Justin He
2021-06-24 6:05 ` [PATCH 01/14] d_path: "\0" is {0,0}, not {0} Justin He
2021-05-19 2:39 ` [PATCHSET] d_path cleanups Linus Torvalds
2021-06-22 14:00 ` Justin He
2021-05-09 2:20 ` [PATCH RFC 1/3] fs: introduce helper d_path_fast() Al Viro
2021-05-09 4:58 ` Al Viro
2021-05-10 16:16 ` Eric W. Biederman
2021-05-10 15:07 ` Justin He
2021-05-10 17:03 ` Linus Torvalds
2021-05-08 12:25 ` [PATCH RFC 2/3] lib/vsprintf.c: make %pD print full path for file Jia He
2021-05-10 3:46 ` Sergey Senozhatsky
2021-05-10 13:04 ` Petr Mladek
2021-05-10 14:25 ` Justin He
2021-05-27 7:20 ` Justin He
2021-05-27 9:14 ` Petr Mladek
2021-05-08 12:25 ` [PATCH RFC 3/3] s390/hmcdrv: remove the redundant directory path in debug message Jia He
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