The patch titled
vt: rework the console spawning variables
has been removed from the -mm tree. Its filename is
vt-rework-the-console-spawning-variables.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: vt: rework the console spawning variables
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
This is such a rare path it took me a while to figure out how to test
this after soring out the locking.
This patch does several things.
- The variables used are moved into a structure and declared in vt_kern.h
- A spinlock is added so we don't have SMP races updating the values.
- Instead of raw pid_t value a struct_pid is used to guard against
pid wrap around issues, if the daemon to spawn a new console dies.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/char/keyboard.c | 16 ++++++++++++----
drivers/char/vt_ioctl.c | 9 ++++++---
include/linux/vt_kern.h | 7 +++++++
3 files changed, 25 insertions(+), 7 deletions(-)
diff -puN drivers/char/keyboard.c~vt-rework-the-console-spawning-variables drivers/char/keyboard.c
--- a/drivers/char/keyboard.c~vt-rework-the-console-spawning-variables
+++ a/drivers/char/keyboard.c
@@ -108,7 +108,11 @@ const int NR_TYPES = ARRAY_SIZE(max_vals
struct kbd_struct kbd_table[MAX_NR_CONSOLES];
static struct kbd_struct *kbd = kbd_table;
-int spawnpid, spawnsig;
+struct vt_spawn_console vt_spawn_con = {
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pid = NULL,
+ .sig = 0,
+};
/*
* Variables exported for vt.c
@@ -578,9 +582,13 @@ static void fn_compose(struct vc_data *v
static void fn_spawn_con(struct vc_data *vc, struct pt_regs *regs)
{
- if (spawnpid)
- if (kill_proc(spawnpid, spawnsig, 1))
- spawnpid = 0;
+ spin_lock(&vt_spawn_con.lock);
+ if (vt_spawn_con.pid)
+ if (kill_pid(vt_spawn_con.pid, vt_spawn_con.sig, 1)) {
+ put_pid(vt_spawn_con.pid);
+ vt_spawn_con.pid = NULL;
+ }
+ spin_unlock(&vt_spawn_con.lock);
}
static void fn_SAK(struct vc_data *vc, struct pt_regs *regs)
diff -puN drivers/char/vt_ioctl.c~vt-rework-the-console-spawning-variables drivers/char/vt_ioctl.c
--- a/drivers/char/vt_ioctl.c~vt-rework-the-console-spawning-variables
+++ a/drivers/char/vt_ioctl.c
@@ -645,13 +645,16 @@ int vt_ioctl(struct tty_struct *tty, str
*/
case KDSIGACCEPT:
{
- extern int spawnpid, spawnsig;
if (!perm || !capable(CAP_KILL))
return -EPERM;
if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
return -EINVAL;
- spawnpid = current->pid;
- spawnsig = arg;
+
+ spin_lock_irq(&vt_spawn_con.lock);
+ put_pid(vt_spawn_con.pid);
+ vt_spawn_con.pid = get_pid(task_pid(current));
+ vt_spawn_con.sig = arg;
+ spin_unlock_irq(&vt_spawn_con.lock);
return 0;
}
diff -puN include/linux/vt_kern.h~vt-rework-the-console-spawning-variables include/linux/vt_kern.h
--- a/include/linux/vt_kern.h~vt-rework-the-console-spawning-variables
+++ a/include/linux/vt_kern.h
@@ -84,4 +84,11 @@ void reset_vc(struct vc_data *vc);
extern char con_buf[CON_BUF_SIZE];
extern struct semaphore con_buf_sem;
+struct vt_spawn_console {
+ spinlock_t lock;
+ struct pid *pid;
+ int sig;
+};
+extern struct vt_spawn_console vt_spawn_con;
+
#endif /* _VT_KERN_H */
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
origin.patch
namespaces-utsname-introduce-temporary-helpers.patch
git-scsi-misc.patch
revert-insert-ioapics-and-local-apic-into-resource-map.patch
insert-local-and-io-apics-into-resource-map.patch
genirq-irq-convert-the-move_irq-flag-from-a-32bit-word-to-a-single-bit.patch
genirq-irq-add-moved_masked_irq.patch
genirq-x86_64-irq-reenable-migrating-irqs-to-other-cpus.patch
genirq-msi-simplify-msi-enable-and-disable.patch
genirq-msi-make-the-msi-boolean-tests-return-either-0-or-1.patch
genirq-msi-implement-helper-functions-read_msi_msg-and-write_msi_msg.patch
genirq-msi-refactor-the-msi_ops.patch
genirq-msi-simplify-the-msi-irq-limit-policy.patch
genirq-irq-add-a-dynamic-irq-creation-api.patch
genirq-ia64-irq-dynamic-irq-support.patch
genirq-i386-irq-dynamic-irq-support.patch
genirq-x86_64-irq-dynamic-irq-support.patch
genirq-msi-make-the-msi-code-irq-based-and-not-vector-based.patch
genirq-x86_64-irq-move-msi-message-composition-into-io_apicc.patch
genirq-i386-irq-move-msi-message-composition-into-io_apicc.patch
genirq-msi-only-build-msi-apicc-on-ia64.patch
genirq-msi-only-build-msi-apicc-on-ia64-fix.patch
genirq-x86_64-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-i386-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-irq-remove-msi-hacks.patch
genirq-irq-generalize-the-check-for-hardirq_bits.patch
genirq-x86_64-irq-make-the-external-irq-handlers-report-their-vector-not-the-irq-number.patch
genirq-x86_64-irq-make-vector_irq-per-cpu.patch
genirq-x86_64-irq-make-vector_irq-per-cpu-fix.patch
genirq-x86_64-irq-make-vector_irq-per-cpu-warning-fix.patch
genirq-x86_64-irq-kill-gsi_irq_sharing.patch
genirq-x86_64-irq-kill-irq-compression.patch
add-hypertransport-capability-defines.patch
add-hypertransport-capability-defines-fix.patch
initial-generic-hypertransport-interrupt-support.patch
initial-generic-hypertransport-interrupt-support-Kconfig-fix.patch
msi-simplify-msi-sanity-checks-by-adding-with-generic-irq-code.patch
msi-only-use-a-single-irq_chip-for-msi-interrupts.patch
msi-refactor-and-move-the-msi-irq_chip-into-the-arch-code.patch
msi-move-the-ia64-code-into-arch-ia64.patch
htirq-tidy-up-the-htirq-code.patch
genirq-clean-up-irq-flow-type-naming.patch
pidhash-temporary-debug-checks.patch
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