Messages in this thread Patch in this message | | | From | Cong Wang <> | Subject | [PATCH 2/7] module: take rcu_read_lock_sched for find_symbol | Date | Thu, 15 Mar 2012 22:48:56 +0800 |
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find_symbol() iterates module list with list_for_each_entry_rcu() should its caller should hold rcu_read_lock_sched().
This patch changes the module_mutex to rcu_read_lock_sched in resolve_symbol() and adds rcu_read_lock_sched in verify_export_symbols().
Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> --- kernel/module.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c index 6f6a3fd..b31b23f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1174,7 +1174,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod, const unsigned long *crc; int err; - mutex_lock(&module_mutex); + rcu_read_lock_sched(); sym = find_symbol(name, &owner, &crc, !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true); if (!sym) @@ -1196,7 +1196,7 @@ getname: /* We must make copy under the lock if we failed to get ref. */ strncpy(ownername, module_name(owner), MODULE_NAME_LEN); unlock: - mutex_unlock(&module_mutex); + rcu_read_unlock_sched(); return sym; } @@ -1844,6 +1844,7 @@ static int verify_export_symbols(struct module *mod) #endif }; + rcu_read_lock_sched(); for (i = 0; i < ARRAY_SIZE(arr); i++) { for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) { if (find_symbol(s->name, &owner, NULL, true, false)) { @@ -1851,10 +1852,12 @@ static int verify_export_symbols(struct module *mod) "%s: exports duplicate symbol %s" " (owned by %s)\n", mod->name, s->name, module_name(owner)); + rcu_read_unlock_sched(); return -ENOEXEC; } } } + rcu_read_unlock_sched(); return 0; } -- 1.7.7.6
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