From: Jeremy Fitzhardinge <jeremy@goop.org>
I'm resending my patch to fix this problem. To recap: every task_struct
has its own copy of the thread group's pgrp. Only the thread group
leader is allowed to change the tgrp's pgrp, but it only updates its own
copy of pgrp, while all the other threads in the tgrp use the old value
they inherited on creation.
This patch simply updates all the other thread's pgrp when the tgrp
leader changes pgrp. Ulrich has already expressed reservations about
this patch since it is (1) incomplete (it doesn't cover the case of
other ids which have similar problems), (2) racy (it doesn't synchronize
with other threads looking at the task pgrp, so they could see an
inconsistent view) and (3) slow (it takes linear time with respect to
the number of threads in the tgrp).
My reaction is that (1) it fixes the actual bug I'm encountering in a
real program. (2) doesn't really matter for pgrp, since it is mostly an
issue with respect to the terminal job-control code (which is even more
broken without this patch. Regarding (3), I think there are very few
programs which have a large number of threads which change process group
id on a regular basis (a heavily multi-threaded job-control shell?).
Ulrich also said he has a (proposed?) much better fix, which I've been
looking forward to. I'm submitting this patch as a stop-gap fix for a
real bug, and perhaps to prompt the improved patch.
An alternative fix, at least for pgrp, is to change all references to
->pgrp to group_leader->pgrp. This may be sufficient on its own, but it
would be a reasonably intrusive patch (I count 95 instances in 32 files
in the 2.6.0-test3-mm3 tree).
DESC
use group_leader->pgrp (was Re: setpgid and threads)
EDESC
From: Jeremy Fitzhardinge <jeremy@goop.org>
Here's a patch to use group_leader->pgrp rather than just ->pgrp so that
all threads in a group appear to have the same process group ID. This
is against 2.6.0-test4-mm6, and so it backs out the previous patch to
kernel/sys.c.
I'm running this now, and it seems to work, including the original test
with which I noticed the original problem. I can't claim to have
heavily tested it though. I think I've compiled all the affected code,
except the non-x86 arch-specific stuff. The only mildly subtle stuff
seems to be in around the handling of execve() in kernel/pid.c.
arch/h8300/kernel/signal.c | 2 +-
arch/m68k/kernel/signal.c | 2 +-
arch/m68knommu/kernel/signal.c | 2 +-
arch/mips/kernel/irixelf.c | 2 +-
arch/mips/kernel/irixsig.c | 2 +-
arch/mips/kernel/sysirix.c | 4 ++--
arch/sparc64/solaris/misc.c | 4 ++--
drivers/char/n_tty.c | 6 +++---
drivers/char/rocket.c | 2 +-
drivers/char/tty_io.c | 10 +++++-----
fs/autofs/autofs_i.h | 2 +-
fs/autofs/inode.c | 2 +-
fs/autofs/root.c | 4 ++--
fs/autofs4/autofs_i.h | 2 +-
fs/autofs4/inode.c | 4 ++--
fs/autofs4/root.c | 4 ++--
fs/binfmt_elf.c | 4 ++--
fs/coda/upcall.c | 2 +-
fs/devfs/base.c | 6 +++---
fs/proc/array.c | 2 +-
include/linux/sched.h | 9 +++++++--
kernel/exit.c | 24 ++++++++++++------------
kernel/fork.c | 2 +-
kernel/pid.c | 4 ++--
kernel/signal.c | 4 ++--
kernel/sys.c | 17 +++++++++--------
26 files changed, 67 insertions(+), 61 deletions(-)
diff -puN kernel/sys.c~group_leader-rework kernel/sys.c
--- 25/kernel/sys.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/kernel/sys.c 2003-09-08 22:47:18.000000000 -0700
@@ -290,7 +290,7 @@ asmlinkage long sys_setpriority(int whic
break;
case PRIO_PGRP:
if (!who)
- who = current->pgrp;
+ who = process_group(current);
for_each_task_pid(who, PIDTYPE_PGID, p, l, pid)
error = set_one_prio(p, niceval, error);
break;
@@ -346,7 +346,7 @@ asmlinkage long sys_getpriority(int whic
break;
case PRIO_PGRP:
if (!who)
- who = current->pgrp;
+ who = process_group(current);
for_each_task_pid(who, PIDTYPE_PGID, p, l, pid) {
niceval = 20 - task_nice(p);
if (niceval > retval)
@@ -979,11 +979,12 @@ ok_pgid:
if (err)
goto out;
- if (p->pgrp != pgid) {
+ if (process_group(p) != pgid) {
detach_pid(p, PIDTYPE_PGID);
- p->pgrp = pgid;
+ p->group_leader->__pgrp = pgid;
attach_pid(p, PIDTYPE_PGID, pgid);
}
+
err = 0;
out:
/* All paths lead to here, thus we are safe. -DaveM */
@@ -994,7 +995,7 @@ out:
asmlinkage long sys_getpgid(pid_t pid)
{
if (!pid) {
- return current->pgrp;
+ return process_group(current);
} else {
int retval;
struct task_struct *p;
@@ -1006,7 +1007,7 @@ asmlinkage long sys_getpgid(pid_t pid)
if (p) {
retval = security_task_getpgid(p);
if (!retval)
- retval = p->pgrp;
+ retval = process_group(p);
}
read_unlock(&tasklist_lock);
return retval;
@@ -1016,7 +1017,7 @@ asmlinkage long sys_getpgid(pid_t pid)
asmlinkage long sys_getpgrp(void)
{
/* SMP - assuming writes are word atomic this is fine */
- return current->pgrp;
+ return process_group(current);
}
asmlinkage long sys_getsid(pid_t pid)
@@ -1059,7 +1060,7 @@ asmlinkage long sys_setsid(void)
__set_special_pids(current->pid, current->pid);
current->tty = NULL;
current->tty_old_pgrp = 0;
- err = current->pgrp;
+ err = process_group(current);
out:
write_unlock_irq(&tasklist_lock);
return err;
diff -puN arch/h8300/kernel/signal.c~group_leader-rework arch/h8300/kernel/signal.c
--- 25/arch/h8300/kernel/signal.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/arch/h8300/kernel/signal.c 2003-09-08 22:47:18.000000000 -0700
@@ -593,7 +593,7 @@ asmlinkage int do_signal(sigset_t *oldse
continue;
case SIGTSTP: case SIGTTIN: case SIGTTOU:
- if (is_orphaned_pgrp(current->pgrp))
+ if (is_orphaned_pgrp(process_group(current)))
continue;
/* FALLTHRU */
diff -puN arch/m68k/kernel/signal.c~group_leader-rework arch/m68k/kernel/signal.c
--- 25/arch/m68k/kernel/signal.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/arch/m68k/kernel/signal.c 2003-09-08 22:47:18.000000000 -0700
@@ -1082,7 +1082,7 @@ asmlinkage int do_signal(sigset_t *oldse
continue;
case SIGTSTP: case SIGTTIN: case SIGTTOU:
- if (is_orphaned_pgrp(current->pgrp))
+ if (is_orphaned_pgrp(process_group(current)))
continue;
/* FALLTHRU */
diff -puN arch/m68knommu/kernel/signal.c~group_leader-rework arch/m68knommu/kernel/signal.c
--- 25/arch/m68knommu/kernel/signal.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/arch/m68knommu/kernel/signal.c 2003-09-08 22:47:18.000000000 -0700
@@ -841,7 +841,7 @@ asmlinkage int do_signal(sigset_t *oldse
continue;
case SIGTSTP: case SIGTTIN: case SIGTTOU:
- if (is_orphaned_pgrp(current->pgrp))
+ if (is_orphaned_pgrp(process_group(current)))
continue;
/* FALLTHRU */
diff -puN arch/mips/kernel/irixelf.c~group_leader-rework arch/mips/kernel/irixelf.c
--- 25/arch/mips/kernel/irixelf.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/arch/mips/kernel/irixelf.c 2003-09-08 22:47:18.000000000 -0700
@@ -1129,7 +1129,7 @@ static int irix_core_dump(long signr, st
prstatus.pr_sighold = current->blocked.sig[0];
psinfo.pr_pid = prstatus.pr_pid = current->pid;
psinfo.pr_ppid = prstatus.pr_ppid = current->parent->pid;
- psinfo.pr_pgrp = prstatus.pr_pgrp = current->pgrp;
+ psinfo.pr_pgrp = prstatus.pr_pgrp = process_group(current);
psinfo.pr_sid = prstatus.pr_sid = current->session;
prstatus.pr_utime.tv_sec = CT_TO_SECS(current->utime);
prstatus.pr_utime.tv_usec = CT_TO_USECS(current->utime);
diff -puN arch/mips/kernel/irixsig.c~group_leader-rework arch/mips/kernel/irixsig.c
--- 25/arch/mips/kernel/irixsig.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/arch/mips/kernel/irixsig.c 2003-09-08 22:47:18.000000000 -0700
@@ -582,7 +582,7 @@ repeat:
p = list_entry(_p,struct task_struct,sibling);
if ((type == P_PID) && p->pid != pid)
continue;
- if ((type == P_PGID) && p->pgrp != pid)
+ if ((type == P_PGID) && process_group(p) != pid)
continue;
if ((p->exit_signal != SIGCHLD))
continue;
diff -puN arch/mips/kernel/sysirix.c~group_leader-rework arch/mips/kernel/sysirix.c
--- 25/arch/mips/kernel/sysirix.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/arch/mips/kernel/sysirix.c 2003-09-08 22:47:18.000000000 -0700
@@ -803,11 +803,11 @@ asmlinkage int irix_setpgrp(int flags)
printk("[%s:%d] setpgrp(%d) ", current->comm, current->pid, flags);
#endif
if(!flags)
- error = current->pgrp;
+ error = process_group(current);
else
error = sys_setsid();
#ifdef DEBUG_PROCGRPS
- printk("returning %d\n", current->pgrp);
+ printk("returning %d\n", process_group(current));
#endif
return error;
diff -puN arch/sparc64/solaris/misc.c~group_leader-rework arch/sparc64/solaris/misc.c
--- 25/arch/sparc64/solaris/misc.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/arch/sparc64/solaris/misc.c 2003-09-08 22:47:18.000000000 -0700
@@ -392,7 +392,7 @@ asmlinkage int solaris_procids(int cmd,
switch (cmd) {
case 0: /* getpgrp */
- return current->pgrp;
+ return process_group(current);
case 1: /* setpgrp */
{
int (*sys_setpgid)(pid_t,pid_t) =
@@ -403,7 +403,7 @@ asmlinkage int solaris_procids(int cmd,
ret = sys_setpgid(0, 0);
if (ret) return ret;
current->tty = NULL;
- return current->pgrp;
+ return process_group(current);
}
case 2: /* getsid */
{
diff -puN drivers/char/n_tty.c~group_leader-rework drivers/char/n_tty.c
--- 25/drivers/char/n_tty.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/drivers/char/n_tty.c 2003-09-08 22:47:18.000000000 -0700
@@ -977,11 +977,11 @@ do_it_again:
if (file->f_op->write != redirected_tty_write && current->tty == tty) {
if (tty->pgrp <= 0)
printk("read_chan: tty->pgrp <= 0!\n");
- else if (current->pgrp != tty->pgrp) {
+ else if (process_group(current) != tty->pgrp) {
if (is_ignored(SIGTTIN) ||
- is_orphaned_pgrp(current->pgrp))
+ is_orphaned_pgrp(process_group(current)))
return -EIO;
- kill_pg(current->pgrp, SIGTTIN, 1);
+ kill_pg(process_group(current), SIGTTIN, 1);
return -ERESTARTSYS;
}
}
diff -puN drivers/char/rocket.c~group_leader-rework drivers/char/rocket.c
--- 25/drivers/char/rocket.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/drivers/char/rocket.c 2003-09-08 22:47:18.000000000 -0700
@@ -956,7 +956,7 @@ static int rp_open(struct tty_struct *tt
* Info->count is now 1; so it's safe to sleep now.
*/
info->session = current->session;
- info->pgrp = current->pgrp;
+ info->pgrp = process_group(current);
if ((info->flags & ROCKET_INITIALIZED) == 0) {
cp = &info->channel;
diff -puN drivers/char/tty_io.c~group_leader-rework drivers/char/tty_io.c
--- 25/drivers/char/tty_io.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/drivers/char/tty_io.c 2003-09-08 22:47:18.000000000 -0700
@@ -325,13 +325,13 @@ int tty_check_change(struct tty_struct *
printk(KERN_WARNING "tty_check_change: tty->pgrp <= 0!\n");
return 0;
}
- if (current->pgrp == tty->pgrp)
+ if (process_group(current) == tty->pgrp)
return 0;
if (is_ignored(SIGTTOU))
return 0;
- if (is_orphaned_pgrp(current->pgrp))
+ if (is_orphaned_pgrp(process_group(current)))
return -EIO;
- (void) kill_pg(current->pgrp,SIGTTOU,1);
+ (void) kill_pg(process_group(current), SIGTTOU, 1);
return -ERESTARTSYS;
}
@@ -1406,7 +1406,7 @@ got_driver:
task_unlock(current);
current->tty_old_pgrp = 0;
tty->session = current->session;
- tty->pgrp = current->pgrp;
+ tty->pgrp = process_group(current);
}
return 0;
}
@@ -1580,7 +1580,7 @@ static int tiocsctty(struct tty_struct *
task_unlock(current);
current->tty_old_pgrp = 0;
tty->session = current->session;
- tty->pgrp = current->pgrp;
+ tty->pgrp = process_group(current);
return 0;
}
diff -puN fs/autofs4/autofs_i.h~group_leader-rework fs/autofs4/autofs_i.h
--- 25/fs/autofs4/autofs_i.h~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/autofs4/autofs_i.h 2003-09-08 22:47:18.000000000 -0700
@@ -113,7 +113,7 @@ static inline struct autofs_info *autofs
filesystem without "magic".) */
static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
- return sbi->catatonic || current->pgrp == sbi->oz_pgrp;
+ return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
}
/* Does a dentry have some pending activity? */
diff -puN fs/autofs4/inode.c~group_leader-rework fs/autofs4/inode.c
--- 25/fs/autofs4/inode.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/autofs4/inode.c 2003-09-08 22:47:18.000000000 -0700
@@ -101,7 +101,7 @@ static int parse_options(char *options,
*uid = current->uid;
*gid = current->gid;
- *pgrp = current->pgrp;
+ *pgrp = process_group(current);
*minproto = AUTOFS_MIN_PROTO_VERSION;
*maxproto = AUTOFS_MAX_PROTO_VERSION;
@@ -192,7 +192,7 @@ int autofs4_fill_super(struct super_bloc
sbi->magic = AUTOFS_SBI_MAGIC;
sbi->catatonic = 0;
sbi->exp_timeout = 0;
- sbi->oz_pgrp = current->pgrp;
+ sbi->oz_pgrp = process_group(current);
sbi->sb = s;
sbi->version = 0;
sbi->queues = NULL;
diff -puN fs/autofs4/root.c~group_leader-rework fs/autofs4/root.c
--- 25/fs/autofs4/root.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/autofs4/root.c 2003-09-08 22:47:18.000000000 -0700
@@ -255,7 +255,7 @@ static struct dentry *autofs4_root_looku
lock_kernel();
oz_mode = autofs4_oz_mode(sbi);
DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
- current->pid, current->pgrp, sbi->catatonic, oz_mode));
+ current->pid, process_group(current), sbi->catatonic, oz_mode));
/*
* Mark the dentry incomplete, but add it. This is needed so
@@ -518,7 +518,7 @@ static int autofs4_root_ioctl(struct ino
struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",
- cmd,arg,sbi,current->pgrp));
+ cmd,arg,sbi,process_group(current)));
if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
_IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
diff -puN fs/autofs/autofs_i.h~group_leader-rework fs/autofs/autofs_i.h
--- 25/fs/autofs/autofs_i.h~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/autofs/autofs_i.h 2003-09-08 22:47:18.000000000 -0700
@@ -123,7 +123,7 @@ static inline struct autofs_sb_info *aut
filesystem without "magic".) */
static inline int autofs_oz_mode(struct autofs_sb_info *sbi) {
- return sbi->catatonic || current->pgrp == sbi->oz_pgrp;
+ return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
}
/* Hash operations */
diff -puN fs/autofs/inode.c~group_leader-rework fs/autofs/inode.c
--- 25/fs/autofs/inode.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/autofs/inode.c 2003-09-08 22:47:18.000000000 -0700
@@ -51,7 +51,7 @@ static int parse_options(char *options,
*uid = current->uid;
*gid = current->gid;
- *pgrp = current->pgrp;
+ *pgrp = process_group(current);
*minproto = *maxproto = AUTOFS_PROTO_VERSION;
diff -puN fs/autofs/root.c~group_leader-rework fs/autofs/root.c
--- 25/fs/autofs/root.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/autofs/root.c 2003-09-08 22:47:19.000000000 -0700
@@ -213,7 +213,7 @@ static struct dentry *autofs_root_lookup
oz_mode = autofs_oz_mode(sbi);
DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
- current->pid, current->pgrp, sbi->catatonic, oz_mode));
+ current->pid, process_group(current), sbi->catatonic, oz_mode));
/*
* Mark the dentry incomplete, but add it. This is needed so
@@ -527,7 +527,7 @@ static int autofs_root_ioctl(struct inod
{
struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
- DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,current->pgrp));
+ DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,process_group(current)));
if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
_IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
diff -puN fs/binfmt_elf.c~group_leader-rework fs/binfmt_elf.c
--- 25/fs/binfmt_elf.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/binfmt_elf.c 2003-09-08 22:47:19.000000000 -0700
@@ -1076,7 +1076,7 @@ static void fill_prstatus(struct elf_prs
prstatus->pr_sighold = p->blocked.sig[0];
prstatus->pr_pid = p->pid;
prstatus->pr_ppid = p->parent->pid;
- prstatus->pr_pgrp = p->pgrp;
+ prstatus->pr_pgrp = process_group(p);
prstatus->pr_sid = p->session;
jiffies_to_timeval(p->utime, &prstatus->pr_utime);
jiffies_to_timeval(p->stime, &prstatus->pr_stime);
@@ -1104,7 +1104,7 @@ static void fill_psinfo(struct elf_prpsi
psinfo->pr_pid = p->pid;
psinfo->pr_ppid = p->parent->pid;
- psinfo->pr_pgrp = p->pgrp;
+ psinfo->pr_pgrp = process_group(p);
psinfo->pr_sid = p->session;
i = p->state ? ffz(~p->state) + 1 : 0;
diff -puN fs/coda/upcall.c~group_leader-rework fs/coda/upcall.c
--- 25/fs/coda/upcall.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/coda/upcall.c 2003-09-08 22:47:19.000000000 -0700
@@ -54,7 +54,7 @@ static void *alloc_upcall(int opcode, in
inp->ih.opcode = opcode;
inp->ih.pid = current->pid;
- inp->ih.pgid = current->pgrp;
+ inp->ih.pgid = process_group(current);
coda_load_creds(&(inp->ih.cred));
return (void*)inp;
diff -puN fs/devfs/base.c~group_leader-rework fs/devfs/base.c
--- 25/fs/devfs/base.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/devfs/base.c 2003-09-08 22:47:19.000000000 -0700
@@ -1334,7 +1334,7 @@ static int is_devfsd_or_child (struct fs
struct task_struct *p = current;
if (p == fs_info->devfsd_task) return (TRUE);
- if (p->pgrp == fs_info->devfsd_pgrp) return (TRUE);
+ if (process_group(p) == fs_info->devfsd_pgrp) return (TRUE);
read_lock(&tasklist_lock);
for ( ; p != &init_task; p = p->real_parent)
{
@@ -2744,8 +2744,8 @@ static int devfsd_ioctl (struct inode *i
}
fs_info->devfsd_task = current;
spin_unlock (&lock);
- fs_info->devfsd_pgrp = (current->pgrp == current->pid) ?
- current->pgrp : 0;
+ fs_info->devfsd_pgrp = (process_group(current) == current->pid) ?
+ process_group(current) : 0;
fs_info->devfsd_file = file;
fs_info->devfsd_info = kmalloc (sizeof *fs_info->devfsd_info,
GFP_KERNEL);
diff -puN fs/proc/array.c~group_leader-rework fs/proc/array.c
--- 25/fs/proc/array.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/fs/proc/array.c 2003-09-08 22:47:19.000000000 -0700
@@ -341,7 +341,7 @@ int proc_pid_stat(struct task_struct *ta
task->comm,
state,
ppid,
- task->pgrp,
+ process_group(task),
task->session,
tty_nr,
tty_pgrp,
diff -puN kernel/exit.c~group_leader-rework kernel/exit.c
--- 25/kernel/exit.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/kernel/exit.c 2003-09-08 22:47:19.000000000 -0700
@@ -152,7 +152,7 @@ static int will_become_orphaned_pgrp(int
|| p->state >= TASK_ZOMBIE
|| p->real_parent->pid == 1)
continue;
- if (p->real_parent->pgrp != pgrp
+ if (process_group(p->real_parent) != pgrp
&& p->real_parent->session == p->session) {
ret = 0;
break;
@@ -247,9 +247,9 @@ void __set_special_pids(pid_t session, p
curr->session = session;
attach_pid(curr, PIDTYPE_SID, session);
}
- if (curr->pgrp != pgrp) {
+ if (process_group(curr) != pgrp) {
detach_pid(curr, PIDTYPE_PGID);
- curr->pgrp = pgrp;
+ curr->group_leader->__pgrp = pgrp;
attach_pid(curr, PIDTYPE_PGID, pgrp);
}
}
@@ -508,9 +508,9 @@ static inline void reparent_thread(task_
* than we are, and it was the only connection
* outside, so the child pgrp is now orphaned.
*/
- if ((p->pgrp != father->pgrp) &&
+ if ((process_group(p) != process_group(father)) &&
(p->session == father->session)) {
- int pgrp = p->pgrp;
+ int pgrp = process_group(p);
if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
__kill_pg_info(SIGHUP, (void *)1, pgrp);
@@ -618,12 +618,12 @@ static void exit_notify(struct task_stru
t = tsk->real_parent;
- if ((t->pgrp != tsk->pgrp) &&
+ if ((process_group(t) != process_group(tsk)) &&
(t->session == tsk->session) &&
- will_become_orphaned_pgrp(tsk->pgrp, tsk) &&
- has_stopped_jobs(tsk->pgrp)) {
- __kill_pg_info(SIGHUP, (void *)1, tsk->pgrp);
- __kill_pg_info(SIGCONT, (void *)1, tsk->pgrp);
+ will_become_orphaned_pgrp(process_group(tsk), tsk) &&
+ has_stopped_jobs(process_group(tsk))) {
+ __kill_pg_info(SIGHUP, (void *)1, process_group(tsk));
+ __kill_pg_info(SIGCONT, (void *)1, process_group(tsk));
}
/* Let father know we died
@@ -813,10 +813,10 @@ static int eligible_child(pid_t pid, int
if (p->pid != pid)
return 0;
} else if (!pid) {
- if (p->pgrp != current->pgrp)
+ if (process_group(p) != process_group(current))
return 0;
} else if (pid != -1) {
- if (p->pgrp != -pid)
+ if (process_group(p) != -pid)
return 0;
}
diff -puN kernel/pid.c~group_leader-rework kernel/pid.c
--- 25/kernel/pid.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/kernel/pid.c 2003-09-08 22:47:19.000000000 -0700
@@ -250,13 +250,13 @@ void switch_exec_pids(task_t *leader, ta
attach_pid(thread, PIDTYPE_PID, thread->pid);
attach_pid(thread, PIDTYPE_TGID, thread->tgid);
- attach_pid(thread, PIDTYPE_PGID, thread->pgrp);
+ attach_pid(thread, PIDTYPE_PGID, leader->__pgrp);
attach_pid(thread, PIDTYPE_SID, thread->session);
list_add_tail(&thread->tasks, &init_task.tasks);
attach_pid(leader, PIDTYPE_PID, leader->pid);
attach_pid(leader, PIDTYPE_TGID, leader->tgid);
- attach_pid(leader, PIDTYPE_PGID, leader->pgrp);
+ attach_pid(leader, PIDTYPE_PGID, leader->__pgrp);
attach_pid(leader, PIDTYPE_SID, leader->session);
}
diff -puN kernel/signal.c~group_leader-rework kernel/signal.c
--- 25/kernel/signal.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/kernel/signal.c 2003-09-08 22:47:19.000000000 -0700
@@ -1139,7 +1139,7 @@ kill_proc_info(int sig, struct siginfo *
static int kill_something_info(int sig, struct siginfo *info, int pid)
{
if (!pid) {
- return kill_pg_info(sig, info, current->pgrp);
+ return kill_pg_info(sig, info, process_group(current));
} else if (pid == -1) {
int retval = 0, count = 0;
struct task_struct * p;
@@ -1798,7 +1798,7 @@ relock:
/* signals can be posted during this window */
- if (is_orphaned_pgrp(current->pgrp))
+ if (is_orphaned_pgrp(process_group(current)))
goto relock;
spin_lock_irq(¤t->sighand->siglock);
diff -puN include/linux/sched.h~group_leader-rework include/linux/sched.h
--- 25/include/linux/sched.h~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/include/linux/sched.h 2003-09-08 22:47:40.000000000 -0700
@@ -362,7 +362,7 @@ struct task_struct {
unsigned long personality;
int did_exec:1;
pid_t pid;
- pid_t pgrp;
+ pid_t __pgrp; /* Accessed via process_group() */
pid_t tty_old_pgrp;
pid_t session;
pid_t tgid;
@@ -377,7 +377,7 @@ struct task_struct {
struct task_struct *parent; /* parent process */
struct list_head children; /* list of my children */
struct list_head sibling; /* linkage in my parent's children list */
- struct task_struct *group_leader;
+ struct task_struct *group_leader; /* threadgroup leader */
/* PID/PID hash table linkage. */
struct pid_link pids[PIDTYPE_MAX];
@@ -463,6 +463,11 @@ struct task_struct {
siginfo_t *last_siginfo; /* For ptrace use. */
};
+static inline pid_t process_group(struct task_struct *tsk)
+{
+ return tsk->group_leader->__pgrp;
+}
+
extern void __put_task_struct(struct task_struct *tsk);
#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
#define put_task_struct(tsk) \
diff -puN kernel/fork.c~group_leader-rework kernel/fork.c
--- 25/kernel/fork.c~group_leader-rework 2003-09-08 22:47:18.000000000 -0700
+++ 25-akpm/kernel/fork.c 2003-09-08 22:47:19.000000000 -0700
@@ -1004,7 +1004,7 @@ struct task_struct *copy_process(unsigne
attach_pid(p, PIDTYPE_PID, p->pid);
if (thread_group_leader(p)) {
attach_pid(p, PIDTYPE_TGID, p->tgid);
- attach_pid(p, PIDTYPE_PGID, p->pgrp);
+ attach_pid(p, PIDTYPE_PGID, process_group(p));
attach_pid(p, PIDTYPE_SID, p->session);
if (p->pid)
__get_cpu_var(process_counts)++;
_