CVS commit: src/sys/miscfs/procfs

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

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.