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Subject[CHECKER] potential races in kernel/*.c mm/*.c net/*ipv4*.c
Date
Hi All,

here are a few more potential races from checking the directories:
kernel/*.c
mm/*.c
net/*ipv4*.c
arch/i386/kernel/*.c
which seem relatively more important that other directories. [If there
are other subdirs that a worth checking let me know --- I am trying to
ensure that if we release race bugs someone will care enough to look
at them.]

The message format is a bit confusing. It gives the places where the
checker thinks there are errors, and then a short list of examples
that made it think that an omitted lock protects the variable.

I do apologize if there are false positives --- I've gone over these,
but sometimes it's very hard to tell if state needs to be protected.

Dawson
-------------------------------------------------------
BUG? pair: lock=<struct sighand_struct.siglock>, var=<recalc_sigpending>
z score=0.90
singles = 1
last = 8
global-var
1 error out of 11 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/ptrace.c:339:ptrace_notify: ERROR: var <recalc_sigpending> not protected by <struct sighand_struct.siglock>(pop=11, s=10) [locked=0] [seen_lock=1]

looks like a bug:

void ptrace_notify(int exit_code)
{
/* Let the debugger run. */
current->exit_code = exit_code;
set_current_state(TASK_STOPPED);
notify_parent(current, SIGCHLD);
schedule();
// Signals sent while we were stopped might set TIF_SIGPENDING.
recalc_sigpending();
other places are carefully guard recalc_sigpending with
siglock:
spin_lock_irqsave(&current->sighand->siglock, flags);
current->notifier = NULL;
current->notifier_data = NULL;
recalc_sigpending();
spin_unlock_irqrestore(&current->sighand->siglock, flags);

====================================
10 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:403:unblock_all_signals: NOTE: var <recalc_sigpending> protected by <struct sighand_struct.siglock> [annot=single] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:unblock_all_signals:400] (pop=11, s=10)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:2183:sys_ssetmask: NOTE: var <recalc_sigpending> protected by <struct sighand_struct.siglock> [annot=last] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sys_ssetmask:2178] (pop=11, s=10)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:2115:sys_sigprocmask: NOTE: var <recalc_sigpending> protected by <struct sighand_struct.siglock> [annot=last] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sys_sigprocmask:2096] (pop=11, s=10)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1848:sys_rt_sigtimedwait: NOTE: var <recalc_sigpending> protected by <struct sighand_struct.siglock> [annot=last] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sys_rt_sigtimedwait:1844] (pop=11, s=10)
/u2/engler/mc/oses/linux/linux-2.5.62/arch/i386/kernel/signal.c:43:sys_sigsuspend: NOTE: var <recalc_sigpending> protected by <struct sighand_struct.siglock> [annot=last] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/arch/i386/kernel/signal.c:sys_sigsuspend:40] (pop=11, s=10)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1656:sigprocmask: NOTE: var <recalc_sigpending> protected by <struct sighand_struct.siglock> [annot=last] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sigprocmask:1640] (pop=11, s=10)
-------------------------------------------------------
BUG? pair: lock=<socket_lock_t.slock>, var=<struct sock.backlog.tail>
z score=2.81
first = 38
1 error out of 41 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/tcp.c:1580:tcp_recvmsg: ERROR: var <struct sock.backlog.tail> not protected by <socket_lock_t.slock>(pop=41, s=40) [locked=0] [seen_lock=1]
unprotected read of backlog.tail but it's unclear if this value
is depended on later.

====================================
40 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/tcp.c:1382:tcp_data_wait: NOTE: var <struct sock.backlog.tail> protected by <socket_lock_t.slock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/tcp.c:tcp_data_wait:1382] (pop=41, s=40)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/tcp.c:1668:tcp_recvmsg: NOTE: var <struct sock.backlog.tail> protected by <socket_lock_t.slock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/tcp.c:tcp_recvmsg:1668] (pop=41, s=40)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/udp.c:691:udp_sendpage: NOTE: var <struct sock.backlog.tail> protected by <socket_lock_t.slock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/udp.c:udp_sendpage:691] (pop=41, s=40)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_sockglue.c:688:ip_getsockopt: NOTE: var <struct sock.backlog.tail> protected by <socket_lock_t.slock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_sockglue.c:ip_getsockopt:688] (pop=41, s=40)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/udp.c:627:udp_sendmsg: NOTE: var <struct sock.backlog.tail> protected by <socket_lock_t.slock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/udp.c:udp_sendmsg:627] (pop=41, s=40)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_sockglue.c:642:ip_setsockopt: NOTE: var <struct sock.backlog.tail> protected by <socket_lock_t.slock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_sockglue.c:ip_setsockopt:642] (pop=41, s=40)
-------------------------------------------------------
BUG? pair: lock=<struct sighand_struct.siglock>, var=<struct task_struct.blocked>
z score=-0.17
singles = 1
first = 3
2 errors out of 9 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/arch/i386/kernel/signal.c:583:do_signal: ERROR: var <struct task_struct.blocked> not protected by <struct sighand_struct.siglock>(pop=9, s=7) [locked=0] [seen_lock=1]
seems like it: other places are careful about getting
current->blocked. here there is no lock at all:

asmlinkage int
sys_sigsuspend(int history0, int history1, old_sigset_t mask)
{
...
regs->eax = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(regs, &saveset))
return -EINTR;
...

// do_signal:

if (!oldset)
oldset = &current->blocked;
====================================
7 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1686:sys_rt_sigprocmask: NOTE: var <struct task_struct.blocked> protected by <struct sighand_struct.siglock> [annot=single] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sys_rt_sigprocmask:1685] (pop=9, s=7)
spin_lock_irq(&current->sighand->siglock);
old_set = current->blocked;
spin_unlock_irq(&current->sighand->siglock)

/u2/engler/mc/oses/linux/linux-2.5.62/arch/i386/kernel/signal.c:70:sys_rt_sigsuspend: NOTE: var <struct task_struct.blocked> protected by <struct sighand_struct.siglock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/arch/i386/kernel/signal.c:sys_rt_sigsuspend:69] (pop=9, s=7)
/u2/engler/mc/oses/linux/linux-2.5.62/arch/i386/kernel/signal.c:41:sys_sigsuspend: NOTE: var <struct task_struct.blocked> protected by <struct sighand_struct.siglock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/arch/i386/kernel/signal.c:sys_sigsuspend:40] (pop=9, s=7)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1641:sigprocmask: NOTE: var <struct task_struct.blocked> protected by <struct sighand_struct.siglock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sigprocmask:1640] (pop=9, s=7)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1846:sys_rt_sigtimedwait: NOTE: var <struct task_struct.blocked> protected by <struct sighand_struct.siglock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sys_rt_sigtimedwait:1844] (pop=9, s=7)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1836:sys_rt_sigtimedwait: NOTE: var <struct task_struct.blocked> protected by <struct sighand_struct.siglock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:sys_rt_sigtimedwait:1824] (pop=9, s=7)
-------------------------------------------------------
BUG? pair: lock=<struct sighand_struct.siglock>, var=<struct task_struct.signal.group_stop_count>
z score=-0.57
singles = 1
2 errors out of 7 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1483:get_signal_to_deliver: ERROR: var <struct task_struct.signal.group_stop_count> not protected by <struct sighand_struct.siglock>(pop=7, s=5) [locked=0] [seen_lock=1]
seems like a race, since someone else could have slipped in and
decremented group_stop_count after the check and before the
acquisition:

if (current->signal->group_stop_count > 0) {
spin_lock_irq(&current->sighand->siglock);
--current->signal->group_stop_count;
spin_unlock_irq(&current->sighand->siglock
====================================
5 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1485:get_signal_to_deliver: NOTE: var <struct task_struct.signal.group_stop_count> protected by <struct sighand_struct.siglock> [annot=single] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:get_signal_to_deliver:1484] (pop=7, s=5)
if (current->signal->group_stop_count > 0) {
spin_lock_irq(&current->sighand->siglock);
--current->signal->group_stop_count;
spin_unlock_irq(&current->sighand->siglock
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:207:recalc_sigpending_tsk: NOTE: var <struct task_struct.signal.group_stop_count> protected by <struct sighand_struct.siglock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exit.c:exit_notify:624
->/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exit.c:exit_notify:631
->/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exit.c:exit_notify:627
->end=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:recalc_sigpending_tsk:207] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/fork.c:958:copy_process: NOTE: var <struct task_struct.signal.group_stop_count> protected by <struct sighand_struct.siglock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/fork.c:copy_process:944] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:1461:get_signal_to_deliver: NOTE: var <struct task_struct.signal.group_stop_count> protected by <struct sighand_struct.siglock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/signal.c:get_signal_to_deliver:1447] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/fork.c:964:copy_process: NOTE: var <struct task_struct.signal.group_stop_count> protected by <struct sighand_struct.siglock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/fork.c:copy_process:944] (pop=7, s=5)
-------------------------------------------------------
BUG? pair: lock=<&cpufreq_driver_sem:struct semaphore:1>, var=<cpufreq_driver,struct cpufreq_driver,1>
z score=1.11
first = 11
global-lock
global-var
1 error out of 13 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:1221:cpufreq_register_driver: ERROR: var <cpufreq_driver,struct cpufreq_driver,1> not protected by <&cpufreq_driver_sem:struct semaphore:1>(pop=13, s=12) [locked=0] [seen_lock=1]
seems like a bug --- the exmaples strongly suggest someone can make the
driver null, in which case i believe the following is open to a race.

if (cpufreq_driver)
return -EBUSY;
if (!driver_data || !driver_data->verify ||
((!driver_data->setpolicy) && (!driver_data->target)))
return -EINVAL;
down(&cpufreq_driver_sem);


====================================
12 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:331:cpufreq_add_dev: NOTE: var <cpufreq_driver,struct cpufreq_driver,1> protected by <&cpufreq_driver_sem:struct semaphore:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:cpufreq_add_dev:330] (pop=13, s=12)
down(&cpufreq_driver_sem);
if (!cpufreq_driver) {
up(&cpufreq_driver_sem);
return -EINVAL;
}

/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:309:show_cpuinfo_min_freq: NOTE: var <cpufreq_driver,struct cpufreq_driver,1> protected by <&cpufreq_driver_sem:struct semaphore:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:show_cpuinfo_min_freq:309] (pop=13, s=12)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:193:show_scaling_governor: NOTE: var <cpufreq_driver,struct cpufreq_driver,1> protected by <&cpufreq_driver_sem:struct semaphore:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:show_scaling_governor:192] (pop=13, s=12)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:1271:cpufreq_unregister_driver: NOTE: var <cpufreq_driver,struct cpufreq_driver,1> protected by <&cpufreq_driver_sem:struct semaphore:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:cpufreq_unregister_driver:1269] (pop=13, s=12)

down(&cpufreq_driver_sem);

if (!cpufreq_driver ||
((driver != cpufreq_driver)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:1062:cpufreq_set_policy: NOTE: var <cpufreq_driver,struct cpufreq_driver,1> protected by <&cpufreq_driver_sem:struct semaphore:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:cpufreq_set_policy:1061] (pop=13, s=12)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:85:cpufreq_parse_governor: NOTE: var <cpufreq_driver,struct cpufreq_driver,1> protected by <&cpufreq_driver_sem:struct semaphore:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/cpufreq.c:cpufreq_parse_governor:84] (pop=13, s=12)
-------------------------------------------------------
BUG? pair: lock=<struct in_device.lock>, var=<struct in_device.mc_list>
z score=-1.00
singles = 1
first = 4
last = 1
3 errors out of 9 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:497:ip_mc_inc_group: ERROR: var <struct in_device.mc_list> not protected by <struct in_device.lock>(pop=9, s=6) [locked=0] [seen_lock=1]
seems like they should have a read lock.


/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:544:ip_mc_dec_group: ERROR: var <struct in_device.mc_list> not protected by <struct in_device.lock>(pop=9, s=6) [locked=0] [seen_lock=1]

read_lock?

/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:571:ip_mc_down: ERROR: var <struct in_device.mc_list> not protected by <struct in_device.lock>(pop=9, s=6) [locked=0] [seen_lock=1]
====================================
6 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:525:ip_mc_inc_group: NOTE: var <struct in_device.mc_list> protected by <struct in_device.lock> [annot=single] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:ip_mc_inc_group:523] (pop=9, s=6)
write_lock_bh(&in_dev->lock);
im->next=in_dev->mc_list;
in_dev->mc_list=im;
write_unlock_bh(&in_dev->lock);


/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:602:ip_mc_destroy_dev: NOTE: var <struct in_device.mc_list> protected by <struct in_device.lock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:ip_mc_destroy_dev:601] (pop=9, s=6)

write_lock_bh(&in_dev->lock);
while ((i = in_dev->mc_list) != NULL) {

/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:773:ip_check_mc: NOTE: var <struct in_device.mc_list> protected by <struct in_device.lock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/igmp.c:ip_check_mc:772] (pop=9, s=6)


read_lock(&in_dev->lock);
for (im=in_dev->mc_list; im; im=im->next) {
if (im->multiaddr == mc_addr) {
read_unlock(&in_dev->lock);
-------------------------------------------------------
BUG? pair: lock=<&fib_rules_lock:rwlock_t:1>, var=<struct fib_rule.r_ifindex>
z score=-1.12
singles = 1
last = 1
global-lock
2 errors out of 5 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:289:fib_rules_detach: ERROR: var <struct fib_rule.r_ifindex> not protected by <&fib_rules_lock:rwlock_t:1>(pop=5, s=3) [locked=0] [seen_lock=1]
this seems pretty busted: they check r->r_ifindex and then
write to it without rechecking that it's the same value:

for (r=fib_rules; r; r=r->r_next) {
if (r->r_ifindex == dev->ifindex) {
write_lock_bh(&fib_rules_lock);
r->r_ifindex = -1;
write_unlock_bh(&fib_rules_lock);
}
}
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:302:fib_rules_attach: ERROR: var <struct fib_rule.r_ifindex> not protected by <&fib_rules_lock:rwlock_t:1>(pop=5, s=3) [locked=0] [seen_lock=1]
same: check, and a write without rechecking:

for (r=fib_rules; r; r=r->r_next) {
if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
write_lock_bh(&fib_rules_lock);
r->r_ifindex = dev->ifindex;
write_unlock_bh(&fib_rules_lock);
====================================
3 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:291:fib_rules_detach: NOTE: var <struct fib_rule.r_ifindex> protected by <&fib_rules_lock:rwlock_t:1> [annot=single] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:fib_rules_detach:290] (pop=5, s=3)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:304:fib_rules_attach: NOTE: var <struct fib_rule.r_ifindex> protected by <&fib_rules_lock:rwlock_t:1> [annot=last] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:fib_rules_attach:303] (pop=5, s=3)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:323:fib_lookup: NOTE: var <struct fib_rule.r_ifindex> protected by <&fib_rules_lock:rwlock_t:1> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:fib_lookup:321] (pop=5, s=3)
-------------------------------------------------------
BUG? pair: lock=<&fib_rules_lock:rwlock_t:1>, var=<*rp,struct fib_rule,0>
z score=-1.50
singles = 1
global-lock
2 errors out of 4 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:111:inet_rtm_delrule: ERROR: var <*rp,struct fib_rule,0> not protected by <&fib_rules_lock:rwlock_t:1>(pop=4, s=2) [locked=0] [seen_lock=1]
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:234:inet_rtm_newrule: ERROR: var <*rp,struct fib_rule,0> not protected by <&fib_rules_lock:rwlock_t:1>(pop=4, s=2) [locked=0] [seen_lock=1]
sure seems like the code is depending on state from outside the
critical section:

while ( (r = *rp) != NULL ) {
if (r->r_preference > new_r->r_preference)
break;
rp = &r->r_next;
}
new_r->r_next = r;
atomic_inc(&new_r->r_clntref);
write_lock_bh(&fib_rules_lock);
*rp = new_r;
write_unlock_bh(&fib_rules_lock);

====================================
2 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:243:inet_rtm_newrule: NOTE: var <*rp,struct fib_rule,0> protected by <&fib_rules_lock:rwlock_t:1> [annot=single] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:inet_rtm_newrule:242] (pop=4, s=2)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:129:inet_rtm_delrule: NOTE: var <*rp,struct fib_rule,0> protected by <&fib_rules_lock:rwlock_t:1> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/fib_rules.c:inet_rtm_delrule:128] (pop=4, s=2)
write_lock_bh(&fib_rules_lock);
*rp = r->r_next;
r->r_dead = 1;
write_unlock_bh(&fib_rules_lock);

-------------------------------------------------------
MINOR: not false, just dumb pair: lock=<&exec_domains_lock:rwlock_t:1>, var=<exec_domains,struct exec_domain,1>
z score=0.20
first = 5
global-lock
global-var
1 error out of 6 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:143:unregister_exec_domain: ERROR: var <exec_domains,struct exec_domain,1> not protected by <&exec_domains_lock:rwlock_t:1>(pop=6, s=5) [locked=0] [seen_lock=1]
epp = &exec_domains;
write_lock(&exec_domains_lock);
for (epp = &exec_domains; *epp; epp = &(*epp)->next) {
====================================
5 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:98:lookup_exec_domain: NOTE: var <exec_domains,struct exec_domain,1> protected by <&exec_domains_lock:rwlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:lookup_exec_domain:96] (pop=6, s=5)
read_lock(&exec_domains_lock);

for (ep = exec_domains; ep; ep = ep->next) {
if (pers >= ep->pers_low && pers <= ep->pers_high)
if (try_module_get(ep->module))
goto out;
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:208:get_exec_domain_list: NOTE: var <exec_domains,struct exec_domain,1> protected by <&exec_domains_lock:rwlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:get_exec_domain_list:207] (pop=6, s=5)

read_lock(&exec_domains_lock);
for (ep = exec_domains; ep && len < PAGE_SIZE - 80; ep = ep->next)
len += sprintf(page + len, "%d-%d\t%-16s\t[%s]\n",
ep->pers_low, ep->pers_high, ep->name,

/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:145:unregister_exec_domain: NOTE: var <exec_domains,struct exec_domain,1> protected by <&exec_domains_lock:rwlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:unregister_exec_domain:144] (pop=6, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:83:lookup_exec_domain: NOTE: var <exec_domains,struct exec_domain,1> protected by <&exec_domains_lock:rwlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:lookup_exec_domain:82] (pop=6, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:124:register_exec_domain: NOTE: var <exec_domains,struct exec_domain,1> protected by <&exec_domains_lock:rwlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/exec_domain.c:register_exec_domain:123] (pop=6, s=5)
-------------------------------------------------------
BUG? pair: lock=<&logbuf_lock:spinlock_t:1>, var=<log_start,unsigned int,1>
z score=-0.57
first = 3
last = 1
global-lock
global-var
2 errors out of 7 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:179:do_syslog: ERROR: var <log_start,unsigned int,1> not protected by <&logbuf_lock:spinlock_t:1>(pop=7, s=5) [locked=0] [seen_lock=1]
supposed to protect log start?

====================================
5 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:625:register_console: NOTE: var <log_start,unsigned int,1> protected by <&logbuf_lock:spinlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:register_console:624] (pop=7, s=5)
spin_lock_irqsave(&logbuf_lock, flags);
con_start = log_start;
spin_unlock_irqrestore(&logbuf_lock, flags);

/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:184:do_syslog: NOTE: var <log_start,unsigned int,1> protected by <&logbuf_lock:spinlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:do_syslog:183] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:498:release_console_sem: NOTE: var <log_start,unsigned int,1> protected by <&logbuf_lock:spinlock_t:1> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:release_console_sem:497] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:186:do_syslog: NOTE: var <log_start,unsigned int,1> protected by <&logbuf_lock:spinlock_t:1> [annot=last] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:do_syslog:183] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:365:emit_log_char: NOTE: var <log_start,unsigned int,1> protected by <&logbuf_lock:spinlock_t:1> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:printk:403
->/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:printk:423
->end=/u2/engler/mc/oses/linux/linux-2.5.62/kernel/printk.c:emit_log_char:365] (pop=7, s=5)
-------------------------------------------------------
BUG? pair: lock=<struct shmem_inode_info.lock>, var=<struct shmem_inode_info.next_index>
z score=0.20
first = 2
1 error out of 6 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:385:shmem_truncate: ERROR: var <struct shmem_inode_info.next_index> not protected by <struct shmem_inode_info.lock>(pop=6, s=5) [locked=0] [seen_lock=1]
seems like a potential race, since info_next_index seems like it could
get decreased in the meantime violating the if-stmt:

if (idx >= info->next_index)
return;
spin_lock(&info->lock);
limit = info->next_index;


====================================
5 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:389:shmem_truncate: NOTE: var <struct shmem_inode_info.next_index> protected by <struct shmem_inode_info.lock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:shmem_truncate:388] (pop=6, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:582:shmem_unuse_inode: NOTE: var <struct shmem_inode_info.next_index> protected by <struct shmem_inode_info.lock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:shmem_unuse_inode:581] (pop=6, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:482:shmem_truncate: NOTE: var <struct shmem_inode_info.next_index> protected by <struct shmem_inode_info.lock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:shmem_truncate:388] (pop=6, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:335:shmem_swp_alloc: NOTE: var <struct shmem_inode_info.next_index> protected by <struct shmem_inode_info.lock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:shmem_swp_alloc:324] (pop=6, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:343:shmem_swp_alloc: NOTE: var <struct shmem_inode_info.next_index> protected by <struct shmem_inode_info.lock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:shmem_getpage:755
->/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:shmem_getpage:757
->end=/u2/engler/mc/oses/linux/linux-2.5.62/mm/shmem.c:shmem_swp_alloc:343] (pop=6, s=5)
-------------------------------------------------------
BUG: pair: lock=<struct ipq.lock>, var=<struct ipq.last_in>
z score=-0.57
first = 2
2 errors out of 7 uses:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:163:ip_frag_destroy: ERROR: var <struct ipq.last_in> not protected by <struct ipq.lock>(pop=7, s=5) [locked=0] [seen_lock=1]
BUG_ON call that looks at last_in

/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:289:ip_frag_intern: ERROR: var <struct ipq.last_in> not protected by <struct ipq.lock>(pop=7, s=5) [locked=0] [seen_lock=1]

seems like a definite bug they read-modify-write it right after
releasing the lock:

write_unlock(&ipfrag_lock);
qp_in->last_in |= COMPLETE;
ipq_put(qp_in);
====================================
5 examples:
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:226:ip_evictor: NOTE: var <struct ipq.last_in> protected by <struct ipq.lock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_evictor:225] (pop=7, s=5)
spin_lock(&qp->lock);
if (!(qp->last_in&COMPLETE))
ipq_kill(qp);
spin_unlock(&qp->lock);
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:249:ip_expire: NOTE: var <struct ipq.last_in> protected by <struct ipq.lock> [annot=first] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_expire:247] (pop=7, s=5)

spin_lock(&qp->lock);

if (qp->last_in & COMPLETE)
goto out;
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:619:ip_defrag: NOTE: var <struct ipq.last_in> protected by <struct ipq.lock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_defrag:615] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:377:ip_frag_queue: NOTE: var <struct ipq.last_in> protected by <struct ipq.lock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_defrag:615
->/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_defrag:617
->end=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_frag_queue:377] (pop=7, s=5)
/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:193:ipq_kill: NOTE: var <struct ipq.last_in> protected by <struct ipq.lock> [annot=none] [level=0] [path=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_defrag:615
->/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_defrag:623
->/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_defrag:623
->/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_defrag:621
->/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ip_frag_reasm:515
->end=/u2/engler/mc/oses/linux/linux-2.5.62/net/ipv4/ip_fragment.c:ipq_kill:193] (pop=7, s=5)
-------------------------------------------------------
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