diff options
| author | Liam R. Howlett (Oracle) <liam@infradead.org> | 2026-08-21 15:26:10 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-08-24 18:43:28 -0700 |
| commit | 8f2109843137da8068f19a120d79e58ef3838429 (patch) | |
| tree | 088004805a26ac05fcd9d43b9d4b238185f3ffea /include/linux | |
| parent | 9e32ec53b1ec2ab28b29c82a95a65bf3d3a5d32c (diff) | |
locking/lockdep: add sequence counter to held_lock
Add an 8 bit small sequence counter to the held_lock struct to detect if
the lock as been dropped and reacquired. This is useful when a data
structure depends on a constant locking context, but is not able to detect
locking and unlocking of the lock through its own API.
Since the __lock_unpin_lock() will no longer detect underflow by casting
the unsigned int to a signed int, update the casting code to use a temp
variable for calculations using a signed int.
Link: https://lore.kernel.org/20260821192627.4085470-3-liam@infradead.org
Signed-off-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/all/h3tpnj5kzcrxms5picmimtkpg4aypcpip5wbd6bt2rpdj5k7eb@nhtzs3lefrkq/
Cc: Breno Leitao <leitao@debian.org>
Cc: Chris Mason <clm@meta.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joe Perches <joe@perches.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/lockdep.h | 3 | ||||
| -rw-r--r-- | include/linux/lockdep_types.h | 3 | ||||
| -rw-r--r-- | include/linux/sched.h | 1 |
3 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 621566345406..a6451ecbbe9a 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -273,6 +273,9 @@ extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock); extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie); extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); +extern u32 lock_sequence(struct lockdep_map *lock); +#define lockdep_sequence(lock) lock_sequence(&(lock)->dep_map) + #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) #define lockdep_assert(cond) \ diff --git a/include/linux/lockdep_types.h b/include/linux/lockdep_types.h index eae115a26488..55c4b152fedf 100644 --- a/include/linux/lockdep_types.h +++ b/include/linux/lockdep_types.h @@ -253,7 +253,8 @@ struct held_lock { unsigned int hardirqs_off:1; unsigned int sync:1; unsigned int references:11; /* 32 bits */ - unsigned int pin_count; + unsigned int pin_count:24; + unsigned int seq_count:8; }; #else /* !CONFIG_LOCKDEP */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 373bcc0598d1..14d5ce8dd613 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1288,6 +1288,7 @@ struct task_struct { u64 curr_chain_key; int lockdep_depth; unsigned int lockdep_recursion; + unsigned int lockdep_seq; struct held_lock held_locks[MAX_LOCK_DEPTH]; #endif |