diff options
| author | Zqiang <qiang1.zhang@intel.com> | 2022-07-01 10:44:04 +0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-08-31 05:03:14 -0700 |
| commit | 6ca0292ccf968e0132e64d6a699d36ba3e92cb81 (patch) | |
| tree | e35b8248fe746aeabfbc0abfd14c3c9d1a93acc5 /kernel/rcu/tiny.c | |
| parent | fcb42c9a77d490ed0974e4d394519481aa06e585 (diff) | |
rcu: Make tiny RCU support leak callbacks for debug-object errors
Currently, only Tree RCU leaks callbacks setting when it detects a
duplicate call_rcu(). This commit causes Tiny RCU to also leak
callbacks in this situation.
Because this is Tiny RCU, kernel size is important:
1. CONFIG_TINY_RCU=y and CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
(Production kernel)
Original:
text data bss dec hex filename
26290663 20159823 15212544 61663030 3ace736 vmlinux
With this commit:
text data bss dec hex filename
26290663 20159823 15212544 61663030 3ace736 vmlinux
2. CONFIG_TINY_RCU=y and CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
(Debugging kernel)
Original:
text data bss dec hex filename
26291319 20160143 15212544 61664006 3aceb06 vmlinux
With this commit:
text data bss dec hex filename
26291319 20160431 15212544 61664294 3acec26 vmlinux
These results show that the kernel size is unchanged for production
kernels, as desired.
Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/tiny.c')
| -rw-r--r-- | kernel/rcu/tiny.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c index f0561ee16b9c..943d431b908f 100644 --- a/kernel/rcu/tiny.c +++ b/kernel/rcu/tiny.c @@ -158,6 +158,10 @@ void synchronize_rcu(void) } EXPORT_SYMBOL_GPL(synchronize_rcu); +static void tiny_rcu_leak_callback(struct rcu_head *rhp) +{ +} + /* * Post an RCU callback to be invoked after the end of an RCU grace * period. But since we have but one CPU, that would be after any @@ -165,9 +169,20 @@ EXPORT_SYMBOL_GPL(synchronize_rcu); */ void call_rcu(struct rcu_head *head, rcu_callback_t func) { + static atomic_t doublefrees; unsigned long flags; - debug_rcu_head_queue(head); + if (debug_rcu_head_queue(head)) { + if (atomic_inc_return(&doublefrees) < 4) { + pr_err("%s(): Double-freed CB %p->%pS()!!! ", __func__, head, head->func); + mem_dump_obj(head); + } + + if (!__is_kvfree_rcu_offset((unsigned long)head->func)) + WRITE_ONCE(head->func, tiny_rcu_leak_callback); + return; + } + head->func = func; head->next = NULL; |