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| author | Peter Zijlstra <peterz@infradead.org> | 2015-05-27 11:09:35 +0930 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2015-05-28 11:31:52 +0930 |
| commit | 0be964be0d45084245673c971d72a4b51690231d (patch) | |
| tree | c3d0f0497d325c28f344adda9c3305e75e550c60 /lib/bug.c | |
| parent | bed831f9a251968272dae10a83b512c7db256ef0 (diff) | |
| download | linux-0be964be0d45084245673c971d72a4b51690231d.tar.gz linux-0be964be0d45084245673c971d72a4b51690231d.tar.xz | |
module: Sanitize RCU usage and locking
Currently the RCU usage in module is an inconsistent mess of RCU and
RCU-sched, this is broken for CONFIG_PREEMPT where synchronize_rcu()
does not imply synchronize_sched().
Most usage sites use preempt_{dis,en}able() which is RCU-sched, but
(most of) the modification sites use synchronize_rcu(). With the
exception of the module bug list, which actually uses RCU.
Convert everything over to RCU-sched.
Furthermore add lockdep asserts to all sites, because it's not at all
clear to me the required locking is observed, esp. on exported
functions.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'lib/bug.c')
| -rw-r--r-- | lib/bug.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/lib/bug.c b/lib/bug.c index 0c3bd9552b6f..cff145f032a5 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -66,7 +66,7 @@ static const struct bug_entry *module_find_bug(unsigned long bugaddr) struct module *mod; const struct bug_entry *bug = NULL; - rcu_read_lock(); + rcu_read_lock_sched(); list_for_each_entry_rcu(mod, &module_bug_list, bug_list) { unsigned i; @@ -77,7 +77,7 @@ static const struct bug_entry *module_find_bug(unsigned long bugaddr) } bug = NULL; out: - rcu_read_unlock(); + rcu_read_unlock_sched(); return bug; } @@ -88,6 +88,8 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, char *secstrings; unsigned int i; + lockdep_assert_held(&module_mutex); + mod->bug_table = NULL; mod->num_bugs = 0; @@ -113,6 +115,7 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, void module_bug_cleanup(struct module *mod) { + lockdep_assert_held(&module_mutex); list_del_rcu(&mod->bug_list); } |