NetBSD Problem Report #39913

From www@NetBSD.org  Thu Nov 13 15:47:52 2008
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Date: Thu, 13 Nov 2008 15:47:52 +0000 (UTC)
From: ad@netbsd.org
Reply-To: ad@netbsd.org
To: gnats-bugs@NetBSD.org
Subject: exec, fork, exit hooks need locking
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>Number:         39913
>Category:       kern
>Synopsis:       exec, fork, exit hooks need locking
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Nov 13 15:50:00 +0000 2008
>Closed-Date:    
>Last-Modified:  Thu Apr 18 18:25:01 +0000 2024
>Originator:     Andrew Doran
>Release:        5.99.1
>Organization:
The NetBSD Project
>Environment:
n/a
>Description:
As per summary.

>How-To-Repeat:
Code inspection.
>Fix:
The exechooks can be covered by exec_lock.
Another mechanism will be needed for fork and exit hooks.

>Release-Note:

>Audit-Trail:
From: Andrew Doran <ad@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/39913 CVS commit: src/sys/kern
Date: Fri, 14 Nov 2008 13:01:18 +0000 (UTC)

 Module Name:	src
 Committed By:	ad
 Date:		Fri Nov 14 13:01:18 UTC 2008

 Modified Files:
 	src/sys/kern: kern_subr.c

 Log Message:
 PR kern/39913 exec, fork, exit hooks need locking

 Acquire exec_lock where needed.


 To generate a diff of this commit:
 cvs rdiff -r1.194 -r1.195 src/sys/kern/kern_subr.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

From: Soren Jacobsen <snj@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/39913 CVS commit: [netbsd-5] src/sys/kern
Date: Mon, 17 Nov 2008 18:56:05 +0000 (UTC)

 Module Name:	src
 Committed By:	snj
 Date:		Mon Nov 17 18:56:05 UTC 2008

 Modified Files:
 	src/sys/kern [netbsd-5]: kern_subr.c

 Log Message:
 Pull up following revision(s) (requested by ad in ticket #75):
 	sys/kern/kern_subr.c: revision 1.195
 PR kern/39913 exec, fork, exit hooks need locking
 Acquire exec_lock where needed.


 To generate a diff of this commit:
 cvs rdiff -r1.192 -r1.192.4.1 src/sys/kern/kern_subr.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

State-Changed-From-To: open->feedback
State-Changed-By: oster@NetBSD.org
State-Changed-When: Fri, 18 Nov 2011 21:12:18 +0000
State-Changed-Why:
It appears that this is fixed, and pulled up.  Is there anything further to do here?


State-Changed-From-To: feedback->open
State-Changed-By: dholland@NetBSD.org
State-Changed-When: Mon, 09 Apr 2012 06:02:07 +0000
State-Changed-Why:
ad resigned; someone needs to figure out if this is fully fixed or not


From: "Juergen Hannken-Illjes" <hannken@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/39913 CVS commit: src/sys/kern
Date: Wed, 17 Jan 2024 10:18:42 +0000

 Module Name:	src
 Committed By:	hannken
 Date:		Wed Jan 17 10:18:41 UTC 2024

 Modified Files:
 	src/sys/kern: init_main.c kern_hook.c

 Log Message:
 Protect kernel hooks exechook, exithook and forkhook with rwlock.
 Lock as writer on establish/disestablish and as reader on list traverse.

 For exechook ride "exec_lock" as it is already take as reader when
 traversing the list.  Add local locks for exithook and forkhook.

 Move exec_init before signal_init as signal_init calls exechook_establish()
 that needs "exec_lock".

 PR kern/39913 "exec, fork, exit hooks need locking"


 To generate a diff of this commit:
 cvs rdiff -u -r1.546 -r1.547 src/sys/kern/init_main.c
 cvs rdiff -u -r1.14 -r1.15 src/sys/kern/kern_hook.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

From: "Martin Husemann" <martin@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/39913 CVS commit: [netbsd-10] src/sys
Date: Thu, 18 Apr 2024 18:22:10 +0000

 Module Name:	src
 Committed By:	martin
 Date:		Thu Apr 18 18:22:10 UTC 2024

 Modified Files:
 	src/sys/kern [netbsd-10]: init_main.c kern_hook.c vfs_mount.c
 	src/sys/miscfs/procfs [netbsd-10]: procfs.h procfs_subr.c
 	    procfs_vfsops.c procfs_vnops.c

 Log Message:
 Pull up following revision(s) (requested by hannken in ticket #668):

 	sys/miscfs/procfs/procfs.h: revision 1.83
 	sys/miscfs/procfs/procfs.h: revision 1.84
 	sys/kern/vfs_mount.c: revision 1.104
 	sys/miscfs/procfs/procfs_vnops.c: revision 1.230
 	sys/kern/init_main.c: revision 1.547
 	sys/kern/kern_hook.c: revision 1.15
 	sys/miscfs/procfs/procfs_vfsops.c: revision 1.112
 	sys/miscfs/procfs/procfs_vfsops.c: revision 1.113
 	sys/miscfs/procfs/procfs_vfsops.c: revision 1.114
 	sys/miscfs/procfs/procfs_subr.c: revision 1.117

 Print dangling vnode before panic() to help debug.

 PR kern/57775 ""panic: unmount: dangling vnode" while umounting procfs"
 Protect kernel hooks exechook, exithook and forkhook with rwlock.

 Lock as writer on establish/disestablish and as reader on list traverse.

 For exechook ride "exec_lock" as it is already take as reader when
 traversing the list.  Add local locks for exithook and forkhook.

 Move exec_init before signal_init as signal_init calls exechook_establish()
 that needs "exec_lock".

 PR kern/39913 "exec, fork, exit hooks need locking"

 Add a hashmap to access all procfs nodes by pid.

 Using the exechook to revoke procfs nodes is racy and may deadlock:
 one thread runs doexechooks() -> procfs_revoke_vnodes() and wants to suspend
 the file system for vgone(), while another thread runs a forced unmount,
 has the file system suspended, tries to disestablish the exechook and
 waits for doexechooks() to complete.

 Establish/disestablish the exechook on module load/unload instead
 mount/unmount and use the hashmap to access all procfs nodes for this pid.

 May fix PR kern/57775 ""panic: unmount: dangling vnode" while umounting procfs"

 Remove all procfs nodes for this process on process exit.


 To generate a diff of this commit:
 cvs rdiff -u -r1.541 -r1.541.2.1 src/sys/kern/init_main.c
 cvs rdiff -u -r1.14 -r1.14.2.1 src/sys/kern/kern_hook.c
 cvs rdiff -u -r1.101 -r1.101.2.1 src/sys/kern/vfs_mount.c
 cvs rdiff -u -r1.82 -r1.82.4.1 src/sys/miscfs/procfs/procfs.h
 cvs rdiff -u -r1.116 -r1.116.20.1 src/sys/miscfs/procfs/procfs_subr.c
 cvs rdiff -u -r1.111 -r1.111.4.1 src/sys/miscfs/procfs/procfs_vfsops.c
 cvs rdiff -u -r1.229 -r1.229.4.1 src/sys/miscfs/procfs/procfs_vnops.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

>Unformatted:

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