From: Alan Cox Add tty locking around the audit and accounting code. The whole current->signal-> locking is all deeply strange but it's for someone else to sort out. Add rather than replace the lock for acct.c Signed-off-by: Alan Cox Acked-by: Arjan van de Ven Cc: Al Viro Cc: Oleg Nesterov Signed-off-by: Andrew Morton --- kernel/acct.c | 6 +++++- kernel/auditsc.c | 5 +++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff -puN kernel/acct.c~audit-accounting-tty-locking kernel/acct.c --- a/kernel/acct.c~audit-accounting-tty-locking +++ a/kernel/acct.c @@ -483,10 +483,14 @@ static void do_acct_process(struct file ac.ac_ppid = current->parent->tgid; #endif - read_lock(&tasklist_lock); /* pin current->signal */ + mutex_lock(&tty_mutex); + /* FIXME: Whoever is responsible for current->signal locking needs + to use the same locking all over the kernel and document it */ + read_lock(&tasklist_lock); ac.ac_tty = current->signal->tty ? old_encode_dev(tty_devnum(current->signal->tty)) : 0; read_unlock(&tasklist_lock); + mutex_unlock(&tty_mutex); spin_lock_irq(¤t->sighand->siglock); ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime))); diff -puN kernel/auditsc.c~audit-accounting-tty-locking kernel/auditsc.c --- a/kernel/auditsc.c~audit-accounting-tty-locking +++ a/kernel/auditsc.c @@ -817,6 +817,8 @@ static void audit_log_exit(struct audit_ audit_log_format(ab, " success=%s exit=%ld", (context->return_valid==AUDITSC_SUCCESS)?"yes":"no", context->return_code); + + mutex_lock(&tty_mutex); if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name) tty = tsk->signal->tty->name; else @@ -838,6 +840,9 @@ static void audit_log_exit(struct audit_ context->gid, context->euid, context->suid, context->fsuid, context->egid, context->sgid, context->fsgid, tty); + + mutex_unlock(&tty_mutex); + audit_log_task_info(ab, tsk); if (context->filterkey) { audit_log_format(ab, " key="); _