linux/tools/testing/selftests/proc
Alexey Dobriyan 5bc73bb345 proc: test how it holds up with mapping'less process
Create process without mappings and check

	/proc/*/maps
	/proc/*/numa_maps
	/proc/*/smaps
	/proc/*/smaps_rollup

They must be empty (excluding vsyscall page) or full of zeroes.

Retroactively this test should've caught embarassing /proc/*/smaps_rollup
oops:

[17752.703567] BUG: kernel NULL pointer dereference, address: 0000000000000000
[17752.703580] #PF: supervisor read access in kernel mode
[17752.703583] #PF: error_code(0x0000) - not-present page
[17752.703587] PGD 0 P4D 0
[17752.703593] Oops: 0000 [#1] PREEMPT SMP PTI
[17752.703598] CPU: 0 PID: 60649 Comm: cat Tainted: G        W         5.19.9-100.fc35.x86_64 #1
[17752.703603] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X99 Extreme6/3.1, BIOS P3.30 08/05/2016
[17752.703607] RIP: 0010:show_smaps_rollup+0x159/0x2e0

Note 1:
	ProtectionKey field in /proc/*/smaps is optional,
	so check most of its contents, not everything.

Note 2:
	due to the nature of this test, child process hardly can signal
	its readiness (after unmapping everything!) to parent.
	I feel like "sleep(1)" is justified.
	If you know how to do it without sleep please tell me.

Note 3:
	/proc/*/statm is not tested but can be.

Link: https://lkml.kernel.org/r/Yz3liL6Dn+n2SD8Q@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-11 18:51:11 -07:00
..
.gitignore proc: test how it holds up with mapping'less process 2022-10-11 18:51:11 -07:00
config
fd-001-lookup.c
fd-002-posix-eq.c
fd-003-kthread.c
Makefile proc: test how it holds up with mapping'less process 2022-10-11 18:51:11 -07:00
proc-empty-vm.c proc: test how it holds up with mapping'less process 2022-10-11 18:51:11 -07:00
proc-fsconfig-hidepid.c proc: use human-readable values for hidepid 2020-04-22 10:51:22 -05:00
proc-loadavg-001.c selftests: proc: fix warning: _GNU_SOURCE redefined 2020-11-05 10:08:14 -07:00
proc-multiple-procfs.c
proc-pid-vm.c proc: save LOC in vsyscall test 2022-09-11 21:55:06 -07:00
proc-self-map-files-001.c
proc-self-map-files-002.c
proc-self-syscall.c selftests: proc: fix warning: _GNU_SOURCE redefined 2020-11-05 10:08:14 -07:00
proc-self-wchan.c
proc-subset-pid.c selftests: proc: test subset=pid 2021-05-06 19:24:11 -07:00
proc-tid0.c procfs: do not list TID 0 in /proc/<pid>/task 2021-11-09 10:02:48 -08:00
proc-uptime-001.c
proc-uptime-002.c selftests: proc: fix warning: _GNU_SOURCE redefined 2020-11-05 10:08:14 -07:00
proc-uptime.h
proc.h
read.c proc: mandate ->proc_lseek in "struct proc_ops" 2021-05-06 19:24:11 -07:00
self.c
setns-dcache.c
setns-sysvipc.c
thread-self.c