Re: kern/52598 (/proc/self/exe misbehaves if it's on a null mount)

[Frédéric Fauberteau <triaxx%NetBSD.org@localhost>]

The following reply was made to PR kern/52598; it has been noted by GNATS.

From: =?UTF-8?Q?Fr=C3=A9d=C3=A9ric_Fauberteau?= <triaxx%NetBSD.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: Pierre Pronchery <khorben%defora.org@localhost>, maya%NetBSD.org@localhost,
 christos%NetBSD.org@localhost
Subject: Re: kern/52598 (/proc/self/exe misbehaves if it's on a null mount)
Date: Mon, 13 Jan 2020 23:23:27 +0100

 I tried to apply the changes made by christos to introduce p_path in 
 struct proc to netbsd-8-0-RELEASE:
 cvs rdiff -u -r1.197.2.2 -r1.200 src/sys/miscfs/procfs/procfs_vnops.c
 cvs rdiff -u -r1.340.6.1 -r1.343 src/sys/sys/proc.h
 
 Now I get the following behavior:
 # ls -l /proc/curproc
 lr-xr-xr-x  1 root  wheel  2 Jan 13 23:09 /proc/curproc -> 49
 # ls -l /proc/curproc/
 causes a fatal page fault.
 
 The backtrace I got using crash(1):
 # crash -M netbsd.9.core
 Crash version 8.0, image version 8.0.
 System panicked: trap
 Backtrace from time of crash is available.
 crash> bt
 _KERNEL_OPT_NARCNET() at 0
 ?() at ffff800064978000
 vpanic() at vpanic+0x166
 snprintf() at snprintf
 trap() at trap+0xa00
 --- trap (number 6) ---
 strlen() at strlen+0x20
 VOP_GETATTR() at VOP_GETATTR+0x4d
 vn_stat() at vn_stat+0x3d
 do_sys_statat() at do_sys_statat+0x89
 sys___lstat50() at sys___lstat50+0x25
 syscall() at syscall+0x1ec
 --- syscall (number 441) ---
 7f5df9ca17ba: