The patch titled
tty_io: fix remaining pid struct locking
has been added to the -mm tree. Its filename is
tty_io-fix-remaining-pid-struct-locking.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
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: tty_io: fix remaining pid struct locking
From: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
This fixes the last couple of pid struct locking failures I know about.
Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/tty_io.c | 28 +++++++++++++++++++++++++++-
fs/proc/array.c | 5 ++++-
include/linux/tty.h | 1 +
3 files changed, 32 insertions(+), 2 deletions(-)
diff -puN drivers/char/tty_io.c~tty_io-fix-remaining-pid-struct-locking drivers/char/tty_io.c
--- a/drivers/char/tty_io.c~tty_io-fix-remaining-pid-struct-locking
+++ a/drivers/char/tty_io.c
@@ -3132,6 +3132,27 @@ unlock:
}
/**
+ * tty_get_pgrp - return a ref counted pgrp pid
+ * @tty: tty to read
+ *
+ * Returns a refcounted instance of the pid struct for the process
+ * group controlling the tty.
+ */
+
+struct pid *tty_get_pgrp(struct tty_struct *tty)
+{
+ unsigned long flags;
+ struct pid *pgrp;
+
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
+ pgrp = get_pid(tty->pgrp);
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
+ return pgrp;
+}
+EXPORT_SYMBOL_GPL(tty_get_pgrp);
+
+/**
* tiocgpgrp - get process group
* @tty: tty passed by user
* @real_tty: tty side of the tty pased by the user if a pty else the tty
@@ -3145,13 +3166,18 @@ unlock:
static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
{
+ struct pid *pid;
+ int ret;
/*
* (tty == real_tty) is a cheap way of
* testing if the tty is NOT a master pty.
*/
if (tty == real_tty && current->signal->tty != real_tty)
return -ENOTTY;
- return put_user(pid_vnr(real_tty->pgrp), p);
+ pid = tty_get_pgrp(real_tty);
+ ret = put_user(pid_vnr(pid), p);
+ put_pid(pid);
+ return ret;
}
/**
diff -puN fs/proc/array.c~tty_io-fix-remaining-pid-struct-locking fs/proc/array.c
--- a/fs/proc/array.c~tty_io-fix-remaining-pid-struct-locking
+++ a/fs/proc/array.c
@@ -408,6 +408,7 @@ static int do_task_stat(struct seq_file
unsigned long rsslim = 0;
char tcomm[sizeof(task->comm)];
unsigned long flags;
+ struct pid *pgrp;
state = *get_task_state(task);
vsize = eip = esp = 0;
@@ -429,7 +430,9 @@ static int do_task_stat(struct seq_file
struct signal_struct *sig = task->signal;
if (sig->tty) {
- tty_pgrp = pid_nr_ns(sig->tty->pgrp, ns);
+ pgrp = tty_get_pgrp(sig->tty);
+ tty_pgrp = pid_nr_ns(pgrp, ns);
+ put_pid(pgrp);
tty_nr = new_encode_dev(tty_devnum(sig->tty));
}
diff -puN include/linux/tty.h~tty_io-fix-remaining-pid-struct-locking include/linux/tty.h
--- a/include/linux/tty.h~tty_io-fix-remaining-pid-struct-locking
+++ a/include/linux/tty.h
@@ -297,6 +297,7 @@ extern int tty_read_raw_data(struct tty_
extern void tty_write_message(struct tty_struct *tty, char *msg);
extern int is_current_pgrp_orphaned(void);
+extern struct pid *tty_get_pgrp(struct tty_struct *tty);
extern int is_ignored(int sig);
extern int tty_signal(int sig, struct tty_struct *tty);
extern void tty_hangup(struct tty_struct * tty);
_
Patches currently in -mm which might be from alan@xxxxxxxxxxxxxxxxxxx are
serial-add-pnp-id-gvc0303-for-archtek-3334brv-isa-modem.patch
libata-isolate-and-rework-cable-logic.patch
pata_amd-fix-sparse-warning.patch
pata-i-do-not-think-it-means-what-you-think-it-means.patch
pata-i-do-not-think-it-means-what-you-think-it-means-checkpatch-fixes.patch
drivers-net-8390c-replace-init_modulecleanup_module-with-module_initmodule_exit.patch
8390-split-8390-support-into-a-pausing-and-a-non-pausing-driver-core.patch
parisc-new-termios-definitions.patch
drivers-usb-serial-io_tic-remove-unneeded-null-tty-check.patch
crisv10-prepare-for-bkl-push-down.patch
fix-tty-speed-handling-on-8250.patch
uart_get_baud_rate-stop-mangling-termios.patch
do_task_stat-dont-take-rcu_read_lock.patch
amiserial-prepare-for-locking-relaxation-in-caller.patch
cyclades-prepare-for-relaxed-locking-in-callers.patch
epca-lock_kernel-push-down.patch
esp-lock_kernel-push-down.patch
isicom-prepare-for-lock_kernel-push-down.patch
isicom-istallion-prepare-for-lock_kernel-pushdown.patch
mxser-prepare-for-bkl-pushdown.patch
nozomi-prepare-for-bkl-pushdown.patch
riscom8-prepare-for-bkl-pushdown.patch
rocket-prepare-for-bkl-pushdown.patch
serial167-prepare-to-push-bkl-down-into-drivers.patch
specialix-prepare-for-bkl-pushdown.patch
stallion-prepare-for-bkl-push-down.patch
sx-prepare-for-bkl-pushdown.patch
synclink-series-prepare-for-bkl-pushdown.patch
viocons-bkl-locking.patch
vt_ioctl-prepare-for-bkl-push-down.patch
isdn_tty-prepare-for-bkl-push-down.patch
68360serial-note-that-there-isnt-any-info-mcr-locking.patch
serial_core-prepare-for-bkl-push-down.patch
tty-bkl-pushdown.patch
tty-bkl-pushdown-fix1.patch
redo-locking-of-tty-pgrp.patch
resume-tty-on-susp-and-fix-crnl-order-in-n_tty-line-discipline.patch
tty_io-fix-remaining-pid-struct-locking.patch
put_pid-make-sure-we-dont-free-the-live-pid.patch
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