The patch titled
Subject: pid: delete RESERVED_PIDS
has been added to the -mm tree. Its filename is
pid-delete-reserved_pids.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/pid-delete-reserved_pids.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/pid-delete-reserved_pids.patch
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------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: pid: delete RESERVED_PIDS
RESERVED_PIDS had a noble goal: to protect root from PID exhaustion since
at least ~2.5.40 except it never did that because there was no capability
or uid checks.
Allow small pids to be allocated after rollover, there is nothing sacred
about them.
Resource exhaustion should be handled by rlimits and/or kernel memory
accounting.
Link: http://lkml.kernel.org/r/20170909202629.GA4791@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/pid.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff -puN kernel/pid.c~pid-delete-reserved_pids kernel/pid.c
--- a/kernel/pid.c~pid-delete-reserved_pids
+++ a/kernel/pid.c
@@ -48,9 +48,7 @@ struct pid init_struct_pid = INIT_STRUCT
int pid_max = PID_MAX_DEFAULT;
-#define RESERVED_PIDS 300
-
-int pid_max_min = RESERVED_PIDS + 1;
+int pid_max_min = 301;
int pid_max_max = PID_MAX_LIMIT;
static inline int mk_pid(struct pid_namespace *pid_ns,
@@ -157,13 +155,13 @@ static int alloc_pidmap(struct pid_names
pid = last + 1;
if (pid >= pid_max)
- pid = RESERVED_PIDS;
+ pid = 1;
offset = pid & BITS_PER_PAGE_MASK;
map = &pid_ns->pidmap[pid/BITS_PER_PAGE];
/*
* If last_pid points into the middle of the map->page we
* want to scan this bitmap block twice, the second time
- * we start with offset == 0 (or RESERVED_PIDS).
+ * we start with offset == 0.
*/
max_scan = DIV_ROUND_UP(pid_max, BITS_PER_PAGE) - !offset;
for (i = 0; i <= max_scan; ++i) {
@@ -203,7 +201,7 @@ static int alloc_pidmap(struct pid_names
offset = 0;
} else {
map = &pid_ns->pidmap[0];
- offset = RESERVED_PIDS;
+ offset = 1;
if (unlikely(last == offset))
break;
}
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
proc-uninline-name_to_int.patch
proc-use-do-while-in-name_to_int.patch
seq_file-delete-small-value-optimization.patch
pid-delete-reserved_pids.patch
pid-delete-struct-pidmap-nr_free.patch
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