free_user() could be called in atomic context.
This patch uses non-sleeping cleanup_srcu_struct_quiesced(). At this stage
atomic refcount is zero, thus all read-sections should have been ended.
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: 77f8269606bf ("ipmi: fix use-after-free of user->release_barrier.rda")
Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
Cc: sta...@vger.kernel.org # 4.18
Cc: Yang Yingliang <yangyingli...@huawei.com>
Cc: Corey Minyard <cminy...@mvista.com>
---
drivers/char/ipmi/ipmi_msghandler.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/char/ipmi/ipmi_msghandler.c
b/drivers/char/ipmi/ipmi_msghandler.c
index e8ba67834746..c35f2bcbaa23 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -1260,7 +1260,12 @@ EXPORT_SYMBOL(ipmi_get_smi_info);
static void free_user(struct kref *ref)
{
struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount);
- cleanup_srcu_struct(&user->release_barrier);
+
+ /*
+ * Cleanup without waiting. This could be called in atomic context.
+ * Refcount is zero: all read-sections should have been ended.
+ */
+ cleanup_srcu_struct_quiesced(&user->release_barrier);
kfree(user);
}
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