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author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-12-05 14:46:09 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2007-12-05 14:46:09 (GMT) |
commit | 54561783ee99d73a086f3abbda3e44f87f6bf65b (patch) | |
tree | 73f836a158f9c05ece41cae6cdb80888d9d6ba07 /kernel | |
parent | 856848737bd944c1db3ce0a66bbf67e56bd6f77d (diff) | |
download | linux-fsl-qoriq-54561783ee99d73a086f3abbda3e44f87f6bf65b.tar.xz |
lockdep: in_range() fix
Torsten Kaiser wrote:
| static inline int in_range(const void *start, const void *addr, const void *end)
| {
| return addr >= start && addr <= end;
| }
| This will return true, if addr is in the range of start (including)
| to end (including).
|
| But debug_check_no_locks_freed() seems does:
| const void *mem_to = mem_from + mem_len
| -> mem_to is the last byte of the freed range, that fits in_range
| lock_from = (void *)hlock->instance;
| -> first byte of the lock
| lock_to = (void *)(hlock->instance + 1);
| -> first byte of the next lock, not last byte of the lock that is being checked!
|
| The test is:
| if (!in_range(mem_from, lock_from, mem_to) &&
| !in_range(mem_from, lock_to, mem_to))
| continue;
| So it tests, if the first byte of the lock is in the range that is freed ->OK
| And if the first byte of the *next* lock is in the range that is freed
| -> Not OK.
We can also simplify in_range checks, we need only 2 comparisons, not 4.
If the lock is not in memory range, it should be either at the left of range
or at the right.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/lockdep.c | 22 |
1 files changed, 10 insertions, 12 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 7e2ca7c..0f38962 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3054,11 +3054,6 @@ void __init lockdep_info(void) #endif } -static inline int in_range(const void *start, const void *addr, const void *end) -{ - return addr >= start && addr <= end; -} - static void print_freed_lock_bug(struct task_struct *curr, const void *mem_from, const void *mem_to, struct held_lock *hlock) @@ -3080,6 +3075,13 @@ print_freed_lock_bug(struct task_struct *curr, const void *mem_from, dump_stack(); } +static inline int not_in_range(const void* mem_from, unsigned long mem_len, + const void* lock_from, unsigned long lock_len) +{ + return lock_from + lock_len <= mem_from || + mem_from + mem_len <= lock_from; +} + /* * Called when kernel memory is freed (or unmapped), or if a lock * is destroyed or reinitialized - this code checks whether there is @@ -3087,7 +3089,6 @@ print_freed_lock_bug(struct task_struct *curr, const void *mem_from, */ void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) { - const void *mem_to = mem_from + mem_len, *lock_from, *lock_to; struct task_struct *curr = current; struct held_lock *hlock; unsigned long flags; @@ -3100,14 +3101,11 @@ void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) for (i = 0; i < curr->lockdep_depth; i++) { hlock = curr->held_locks + i; - lock_from = (void *)hlock->instance; - lock_to = (void *)(hlock->instance + 1); - - if (!in_range(mem_from, lock_from, mem_to) && - !in_range(mem_from, lock_to, mem_to)) + if (not_in_range(mem_from, mem_len, hlock->instance, + sizeof(*hlock->instance))) continue; - print_freed_lock_bug(curr, mem_from, mem_to, hlock); + print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); break; } local_irq_restore(flags); |