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seccomp: Replace BUG(!spin_is_locked()) with assert_spin_lock

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Current upstream kernel hangs with mips and powerpc targets in
uniprocessor mode if SECCOMP is configured.

Bisect points to commit dbd952127d ("seccomp: introduce writer locking").
Turns out that code such as
	BUG_ON(!spin_is_locked(&list_lock));
can not be used in uniprocessor mode because spin_is_locked() always
returns false in this configuration, and that assert_spin_locked()
exists for that very purpose and must be used instead.

Fixes: dbd952127d ("seccomp: introduce writer locking")
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Guenter Roeck 2014-08-10 20:50:30 -07:00 committed by Kees Cook
parent c8d6637d04
commit 69f6a34bde
2 changed files with 6 additions and 6 deletions
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2
kernel/fork.c
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@ -1105,7 +1105,7 @@ static void copy_seccomp(struct task_struct *p)
* needed because this new task is not yet running and cannot
* be racing exec.
*/
BUG_ON(!spin_is_locked(&current->sighand->siglock));
assert_spin_locked(&current->sighand->siglock);
/* Ref-count the new filter user, and assign it. */
get_seccomp_filter(current);

10
kernel/seccomp.c
View file

@ -203,7 +203,7 @@ static u32 seccomp_run_filters(int syscall)
static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode)
{
BUG_ON(!spin_is_locked(&current->sighand->siglock));
assert_spin_locked(&current->sighand->siglock);
if (current->seccomp.mode && current->seccomp.mode != seccomp_mode)
return false;
@ -214,7 +214,7 @@ static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode)
static inline void seccomp_assign_mode(struct task_struct *task,
unsigned long seccomp_mode)
{
BUG_ON(!spin_is_locked(&task->sighand->siglock));
assert_spin_locked(&task->sighand->siglock);
task->seccomp.mode = seccomp_mode;
/*
@ -253,7 +253,7 @@ static inline pid_t seccomp_can_sync_threads(void)
struct task_struct *thread, *caller;
BUG_ON(!mutex_is_locked(&current->signal->cred_guard_mutex));
BUG_ON(!spin_is_locked(&current->sighand->siglock));
assert_spin_locked(&current->sighand->siglock);
/* Validate all threads being eligible for synchronization. */
caller = current;
@ -294,7 +294,7 @@ static inline void seccomp_sync_threads(void)
struct task_struct *thread, *caller;
BUG_ON(!mutex_is_locked(&current->signal->cred_guard_mutex));
BUG_ON(!spin_is_locked(&current->sighand->siglock));
assert_spin_locked(&current->sighand->siglock);
/* Synchronize all threads. */
caller = current;
@ -464,7 +464,7 @@ static long seccomp_attach_filter(unsigned int flags,
unsigned long total_insns;
struct seccomp_filter *walker;
BUG_ON(!spin_is_locked(&current->sighand->siglock));
assert_spin_locked(&current->sighand->siglock);
/* Validate resulting filter length. */
total_insns = filter->prog->len;