PR/57775 CVS commit: src/sys/miscfs/procfs

["Juergen Hannken-Illjes" <hannken%netbsd.org@localhost>]

The following reply was made to PR kern/57775; it has been noted by GNATS.

From: "Juergen Hannken-Illjes" <hannken%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/57775 CVS commit: src/sys/miscfs/procfs
Date: Wed, 17 Jan 2024 10:20:12 +0000

 Module Name:	src
 Committed By:	hannken
 Date:		Wed Jan 17 10:20:12 UTC 2024
 
 Modified Files:
 	src/sys/miscfs/procfs: procfs.h procfs_subr.c procfs_vfsops.c
 
 Log Message:
 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"
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.83 -r1.84 src/sys/miscfs/procfs/procfs.h
 cvs rdiff -u -r1.116 -r1.117 src/sys/miscfs/procfs/procfs_subr.c
 cvs rdiff -u -r1.112 -r1.113 src/sys/miscfs/procfs/procfs_vfsops.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.