Commit 3b9a9072 authored by Corey Minyard's avatar Corey Minyard

ipmi: fix sleep-in-atomic in free_user at cleanup SRCU user->release_barrier

free_user() could be called in atomic context.

This patch pushed the free operation off into a workqueue.

Example:

 BUG: sleeping function called from invalid context at kernel/workqueue.c:2856
 in_atomic(): 1, irqs_disabled(): 0, pid: 177, name: ksoftirqd/27
 CPU: 27 PID: 177 Comm: ksoftirqd/27 Not tainted 4.19.25-3 #1
 Hardware name: AIC 1S-HV26-08/MB-DPSB04-06, BIOS IVYBV060 10/21/2015
 Call Trace:
  dump_stack+0x5c/0x7b
  ___might_sleep+0xec/0x110
  __flush_work+0x48/0x1f0
  ? try_to_del_timer_sync+0x4d/0x80
  _cleanup_srcu_struct+0x104/0x140
  free_user+0x18/0x30 [ipmi_msghandler]
  ipmi_free_recv_msg+0x3a/0x50 [ipmi_msghandler]
  deliver_response+0xbd/0xd0 [ipmi_msghandler]
  deliver_local_response+0xe/0x30 [ipmi_msghandler]
  handle_one_recv_msg+0x163/0xc80 [ipmi_msghandler]
  ? dequeue_entity+0xa0/0x960
  handle_new_recv_msgs+0x15c/0x1f0 [ipmi_msghandler]
  tasklet_action_common.isra.22+0x103/0x120
  __do_softirq+0xf8/0x2d7
  run_ksoftirqd+0x26/0x50
  smpboot_thread_fn+0x11d/0x1e0
  kthread+0x103/0x140
  ? sort_range+0x20/0x20
  ? kthread_destroy_worker+0x40/0x40
  ret_from_fork+0x1f/0x40

Fixes: 77f82696 ("ipmi: fix use-after-free of user->release_barrier.rda")
Reported-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org # 5.0
Cc: Yang Yingliang <yangyingliang@huawei.com>
parent a885bcfd
...@@ -214,6 +214,9 @@ struct ipmi_user { ...@@ -214,6 +214,9 @@ struct ipmi_user {
/* Does this interface receive IPMI events? */ /* Does this interface receive IPMI events? */
bool gets_events; bool gets_events;
/* Free must run in process context for RCU cleanup. */
struct work_struct remove_work;
}; };
static struct ipmi_user *acquire_ipmi_user(struct ipmi_user *user, int *index) static struct ipmi_user *acquire_ipmi_user(struct ipmi_user *user, int *index)
...@@ -1157,6 +1160,15 @@ static int intf_err_seq(struct ipmi_smi *intf, ...@@ -1157,6 +1160,15 @@ static int intf_err_seq(struct ipmi_smi *intf,
return rv; return rv;
} }
static void free_user_work(struct work_struct *work)
{
struct ipmi_user *user = container_of(work, struct ipmi_user,
remove_work);
cleanup_srcu_struct(&user->release_barrier);
kfree(user);
}
int ipmi_create_user(unsigned int if_num, int ipmi_create_user(unsigned int if_num,
const struct ipmi_user_hndl *handler, const struct ipmi_user_hndl *handler,
void *handler_data, void *handler_data,
...@@ -1200,6 +1212,8 @@ int ipmi_create_user(unsigned int if_num, ...@@ -1200,6 +1212,8 @@ int ipmi_create_user(unsigned int if_num,
goto out_kfree; goto out_kfree;
found: found:
INIT_WORK(&new_user->remove_work, free_user_work);
rv = init_srcu_struct(&new_user->release_barrier); rv = init_srcu_struct(&new_user->release_barrier);
if (rv) if (rv)
goto out_kfree; goto out_kfree;
...@@ -1260,8 +1274,9 @@ EXPORT_SYMBOL(ipmi_get_smi_info); ...@@ -1260,8 +1274,9 @@ EXPORT_SYMBOL(ipmi_get_smi_info);
static void free_user(struct kref *ref) static void free_user(struct kref *ref)
{ {
struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount); struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount);
cleanup_srcu_struct(&user->release_barrier);
kfree(user); /* SRCU cleanup must happen in task context. */
schedule_work(&user->remove_work);
} }
static void _ipmi_destroy_user(struct ipmi_user *user) static void _ipmi_destroy_user(struct ipmi_user *user)
......
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