From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: proc: fix /proc/loadavg regression
95846ecf9dac508 ("pid: replace pid bitmap implementation with IDR API")
changed last field of /proc/loadavg (last pid allocated) to be off by one:
# unshare -p -f --mount-proc cat /proc/loadavg
0.00 0.00 0.00 1/60 2 <===
It should be 1 after first fork into pid namespace.
This is formally a regression but given how useless this field is
I don't think anyone is affected.
Bug was found by /proc testsuite!
Link: http://lkml.kernel.org/r/20180413175408.GA27246@avx2
Fixes: 95846ecf9dac508 ("pid: replace pid bitmap implementation with IDR API")
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Gargi Sharma <gs051095@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/platforms/cell/spufs/sched.c | 2 +-
fs/proc/loadavg.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff -puN arch/powerpc/platforms/cell/spufs/sched.c~proc-fix-proc-loadavg-regression arch/powerpc/platforms/cell/spufs/sched.c
--- a/arch/powerpc/platforms/cell/spufs/sched.c~proc-fix-proc-loadavg-regression
+++ a/arch/powerpc/platforms/cell/spufs/sched.c
@@ -1093,7 +1093,7 @@ static int show_spu_loadavg(struct seq_f
LOAD_INT(c), LOAD_FRAC(c),
count_active_contexts(),
atomic_read(&nr_spu_contexts),
- idr_get_cursor(&task_active_pid_ns(current)->idr));
+ idr_get_cursor(&task_active_pid_ns(current)->idr) - 1);
return 0;
}
diff -puN fs/proc/loadavg.c~proc-fix-proc-loadavg-regression fs/proc/loadavg.c
--- a/fs/proc/loadavg.c~proc-fix-proc-loadavg-regression
+++ a/fs/proc/loadavg.c
@@ -24,7 +24,7 @@ static int loadavg_proc_show(struct seq_
LOAD_INT(avnrun[1]), LOAD_FRAC(avnrun[1]),
LOAD_INT(avnrun[2]), LOAD_FRAC(avnrun[2]),
nr_running(), nr_threads,
- idr_get_cursor(&task_active_pid_ns(current)->idr));
+ idr_get_cursor(&task_active_pid_ns(current)->idr) - 1);
return 0;
}
_
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