The patch titled
fix setpriority(PRIO_PGRP) thread iterator breakage
has been added to the -mm tree. Its filename is
fix-setpriorityprio_pgrp-thread-iterator-breakage.patch
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See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: fix setpriority(PRIO_PGRP) thread iterator breakage
From: "Ken Chen" <kenchen@xxxxxxxxxx>
When user calls sys_setpriority(PRIO_PGRP ...) on a NPTL style multi-LWP
process, only the task leader of the process is affected, all other
sibling LWP threads didn't receive the setting. The problem was that the
iterator used in sys_setpriority() only iteartes over one task for each
process, ignoring all other sibling thread.
Introduce a new macro do_each_pid_thread / while_each_pid_thread to walk
each thread of a process. Convert 4 call sites in {set/get}priority and
ioprio_{set/get}.
Signed-off-by: Ken Chen <kenchen@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ioprio.c | 8 ++++----
include/linux/pid.h | 9 +++++++++
kernel/sys.c | 8 ++++----
3 files changed, 17 insertions(+), 8 deletions(-)
diff -puN fs/ioprio.c~fix-setpriorityprio_pgrp-thread-iterator-breakage fs/ioprio.c
--- a/fs/ioprio.c~fix-setpriorityprio_pgrp-thread-iterator-breakage
+++ a/fs/ioprio.c
@@ -121,11 +121,11 @@ asmlinkage long sys_ioprio_set(int which
pgrp = task_pgrp(current);
else
pgrp = find_vpid(who);
- do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+ do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
ret = set_task_ioprio(p, ioprio);
if (ret)
break;
- } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+ } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case IOPRIO_WHO_USER:
if (!who)
@@ -210,7 +210,7 @@ asmlinkage long sys_ioprio_get(int which
pgrp = task_pgrp(current);
else
pgrp = find_vpid(who);
- do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+ do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
tmpio = get_task_ioprio(p);
if (tmpio < 0)
continue;
@@ -218,7 +218,7 @@ asmlinkage long sys_ioprio_get(int which
ret = tmpio;
else
ret = ioprio_best(ret, tmpio);
- } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+ } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case IOPRIO_WHO_USER:
if (!who)
diff -puN include/linux/pid.h~fix-setpriorityprio_pgrp-thread-iterator-breakage include/linux/pid.h
--- a/include/linux/pid.h~fix-setpriorityprio_pgrp-thread-iterator-breakage
+++ a/include/linux/pid.h
@@ -161,4 +161,13 @@ pid_t pid_vnr(struct pid *pid);
} \
} while (0)
+#define do_each_pid_thread(pid, type, task) \
+ do_each_pid_task(pid, type, task) { \
+ struct task_struct *tg___ = task; \
+ do {
+
+#define while_each_pid_thread(pid, type, task) \
+ } while_each_thread(tg___, task); \
+ task = tg___; \
+ } while_each_pid_task(pid, type, task)
#endif /* _LINUX_PID_H */
diff -puN kernel/sys.c~fix-setpriorityprio_pgrp-thread-iterator-breakage kernel/sys.c
--- a/kernel/sys.c~fix-setpriorityprio_pgrp-thread-iterator-breakage
+++ a/kernel/sys.c
@@ -175,9 +175,9 @@ asmlinkage long sys_setpriority(int whic
pgrp = find_vpid(who);
else
pgrp = task_pgrp(current);
- do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+ do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
error = set_one_prio(p, niceval, error);
- } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+ } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case PRIO_USER:
user = (struct user_struct *) cred->user;
@@ -236,11 +236,11 @@ asmlinkage long sys_getpriority(int whic
pgrp = find_vpid(who);
else
pgrp = task_pgrp(current);
- do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+ do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
niceval = 20 - task_nice(p);
if (niceval > retval)
retval = niceval;
- } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+ } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case PRIO_USER:
user = (struct user_struct *) cred->user;
_
Patches currently in -mm which might be from kenchen@xxxxxxxxxx are
fix-setpriorityprio_pgrp-thread-iterator-breakage.patch
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