The patch titled
pid: make session_of_pgrp use struct pid instead of pid_t
has been added to the -mm tree. Its filename is
pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: pid: make session_of_pgrp use struct pid instead of pid_t
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
To properly implement a pid namespace I need to deal exclusively in terms of
struct pid, because pid_t values become ambiguous.
To this end session_of_pgrp is transformed to take and return a struct pid
pointer. To avoid the need to worry about reference counting I now require my
caller to hold the appropriate locks. Leaving callers repsonsible for
increasing the reference count if they need access to the result outside of
the locks.
Since session_of_pgrp currently only has one caller and that caller simply
uses only test the result for equality with another process group, the locking
change means I don't actually have to acquire the tasklist_lock at all.
tiocspgrp is also modified to take and release the lock. The logic there is a
little more complicated but nothing I won't need when I convert pgrp of a tty
to a struct pid pointer.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/char/tty_io.c | 24 +++++++++++++++++-------
include/linux/kernel.h | 3 ++-
kernel/exit.c | 16 +++++++---------
3 files changed, 26 insertions(+), 17 deletions(-)
diff -puN drivers/char/tty_io.c~pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t drivers/char/tty_io.c
--- a/drivers/char/tty_io.c~pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t
+++ a/drivers/char/tty_io.c
@@ -2990,7 +2990,8 @@ static int tiocgpgrp(struct tty_struct *
static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
{
- pid_t pgrp;
+ struct pid *pgrp;
+ pid_t pgrp_nr;
int retval = tty_check_change(real_tty);
if (retval == -EIO)
@@ -3001,14 +3002,23 @@ static int tiocspgrp(struct tty_struct *
(current->signal->tty != real_tty) ||
(real_tty->session != process_session(current)))
return -ENOTTY;
- if (get_user(pgrp, p))
+ if (get_user(pgrp_nr, p))
return -EFAULT;
- if (pgrp < 0)
+ if (pgrp_nr < 0)
return -EINVAL;
- if (session_of_pgrp(pgrp) != process_session(current))
- return -EPERM;
- real_tty->pgrp = pgrp;
- return 0;
+ rcu_read_lock();
+ pgrp = find_pid(pgrp_nr);
+ retval = -ESRCH;
+ if (!pgrp)
+ goto out_unlock;
+ retval = -EPERM;
+ if (session_of_pgrp(pgrp) != task_session(current))
+ goto out_unlock;
+ retval = 0;
+ real_tty->pgrp = pgrp_nr;
+out_unlock:
+ rcu_read_unlock();
+ return retval;
}
/**
diff -puN include/linux/kernel.h~pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t include/linux/kernel.h
--- a/include/linux/kernel.h~pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t
+++ a/include/linux/kernel.h
@@ -136,7 +136,8 @@ extern unsigned long long memparse(char
extern int core_kernel_text(unsigned long addr);
extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);
-extern int session_of_pgrp(int pgrp);
+struct pid;
+extern struct pid *session_of_pgrp(struct pid *pgrp);
extern void dump_thread(struct pt_regs *regs, struct user *dump);
diff -puN kernel/exit.c~pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t kernel/exit.c
--- a/kernel/exit.c~pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t
+++ a/kernel/exit.c
@@ -185,21 +185,19 @@ repeat:
* This checks not only the pgrp, but falls back on the pid if no
* satisfactory pgrp is found. I dunno - gdb doesn't work correctly
* without this...
+ *
+ * The caller must hold rcu lock or the tasklist lock.
*/
-int session_of_pgrp(int pgrp)
+struct pid *session_of_pgrp(struct pid *pgrp)
{
struct task_struct *p;
- int sid = 0;
-
- read_lock(&tasklist_lock);
+ struct pid *sid = NULL;
- p = find_task_by_pid_type(PIDTYPE_PGID, pgrp);
+ p = pid_task(pgrp, PIDTYPE_PGID);
if (p == NULL)
- p = find_task_by_pid(pgrp);
+ p = pid_task(pgrp, PIDTYPE_PID);
if (p != NULL)
- sid = process_session(p);
-
- read_unlock(&tasklist_lock);
+ sid = task_session(p);
return sid;
}
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
origin.patch
revert-identifier-to-nsproxy.patch
vt-fix-comments-to-not-refer-to-kill_proc.patch
n_r3964-use-struct-pid-to-track-user-space-clients.patch
smbfs-make-conn_pid-a-struct-pid.patch
ncpfs-use-struct-pid-to-track-the-userspace-watchdog-process.patch
ncpfs-ensure-we-free-wdog_pid-on-parse_option-or-fill_inode-failure.patch
usbatm-update-to-use-the-kthread-api.patch
genapic-optimize-fix-apic-mode-setup-2.patch
genapic-always-use-physical-delivery-mode-on-8-cpus.patch
genapic-remove-es7000-workaround.patch
genapic-remove-clustered-apic-mode.patch
genapic-default-to-physical-mode-on-hotplug-cpu-kernels.patch
vt-refactor-console-sak-processing.patch
sysctl_ms_jiffies-fix-oldlen-semantics.patch
9p-use-kthread_stop-instead-of-sending-a-sigkill.patch
tty-make-__proc_set_tty-static.patch
tty-clarify-disassociate_ctty.patch
tty-fix-the-locking-for-signal-session-in-disassociate_ctty.patch
signal-use-kill_pgrp-not-kill_pg-in-the-sunos-compatibility-code.patch
signal-rewrite-kill_something_info-so-it-uses-newer-helpers.patch
pid-make-session_of_pgrp-use-struct-pid-instead-of-pid_t.patch
pid-use-struct-pid-for-talking-about-process-groups-in-exitc.patch
pid-replace-is_orphaned_pgrp-with-is_current_pgrp_orphaned.patch
tty-update-the-tty-layer-to-work-with-struct-pid.patch
pid-replace-do-while_each_task_pid-with-do-while_each_pid_task.patch
pid-remove-now-unused-do_each_task_pid-and-while_each_task_pid.patch
pid-remove-the-now-unused-kill_pg-kill_pg_info-and-__kill_pg_info.patch
sched2-sched-domain-sysctl-use-ctl_unnumbered.patch
mm-implement-swap-prefetching-use-ctl_unnumbered.patch
readahead-sysctl-parameters-use-ctl_unnumbered.patch
updated-i386-cleanup-apic-code.patch
updated-i386-rework-local-apic-calibration.patch
updated-dynticks-fix-nmi-watchdog.patch
clockevents-core-check-for-clock-event-device-handler-being-non-null-before-calling-it.patch
pidhash-temporary-debug-checks.patch
vdso-print-fatal-signals-use-ctl_unnumbered.patch
-
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