[PATCH 1/2] Revert "ipmi: fix sleep-in-atomic in free_user at cleanup SRCU user->release_barrier"
hulk inclusion category: bugfix bugzilla: 5499 CVE: NA --------------------------- cleanup_srcu_struct_quiesced won't free memory if work_pending() is true, and it will cause a memory leak, so revert it and using mainline patch instead. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/char/ipmi/ipmi_msghandler.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index 0085d32cef46..7510013f28f8 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -1190,12 +1190,7 @@ 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 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); + cleanup_srcu_struct(&user->release_barrier); kfree(user); } -- 2.25.1
From: Corey Minyard <cminyard@mvista.com> commit 3b9a907223d7f6b9d1dadea29436842ae9bcd76d upstream. 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: 77f8269606bf ("ipmi: fix use-after-free of user->release_barrier.rda") Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Corey Minyard <cminyard@mvista.com> Cc: stable@vger.kernel.org # 5.0 Cc: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/char/ipmi/ipmi_msghandler.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index 7510013f28f8..69734b1df792 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -213,6 +213,9 @@ struct ipmi_user { /* Does this interface receive IPMI 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) @@ -1080,6 +1083,15 @@ static int intf_err_seq(struct ipmi_smi *intf, } +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, const struct ipmi_user_hndl *handler, void *handler_data, @@ -1123,6 +1135,8 @@ int ipmi_create_user(unsigned int if_num, goto out_kfree; found: + INIT_WORK(&new_user->remove_work, free_user_work); + rv = init_srcu_struct(&new_user->release_barrier); if (rv) goto out_kfree; @@ -1190,8 +1204,9 @@ 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); - kfree(user); + + /* SRCU cleanup must happen in task context. */ + schedule_work(&user->remove_work); } static void _ipmi_destroy_user(struct ipmi_user *user) -- 2.25.1
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Yang Yingliang