4.16-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ Upstream commit 79eb382b5e06a6dca5806465d7195d686a463ab0 ]
I don't why we need take a single write lock and disable interrupts while setting up debugfs. This is what what happens when we try anyway:
|ccp 0000:03:00.2: enabling device (0000 -> 0002) |BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:69 |in_atomic(): 1, irqs_disabled(): 1, pid: 3, name: kworker/0:0 |irq event stamp: 17150 |hardirqs last enabled at (17149): [<0000000097a18c49>] restore_regs_and_return_to_kernel+0x0/0x23 |hardirqs last disabled at (17150): [<000000000773b3a9>] _raw_write_lock_irqsave+0x1b/0x50 |softirqs last enabled at (17148): [<0000000064d56155>] __do_softirq+0x3b8/0x4c1 |softirqs last disabled at (17125): [<0000000092633c18>] irq_exit+0xb1/0xc0 |CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.16.0-rc2+ #30 |Workqueue: events work_for_cpu_fn |Call Trace: | dump_stack+0x7d/0xb6 | ___might_sleep+0x1eb/0x250 | down_write+0x17/0x60 | start_creating+0x4c/0xe0 | debugfs_create_dir+0x9/0x100 | ccp5_debugfs_setup+0x191/0x1b0 | ccp5_init+0x8a7/0x8c0 | ccp_dev_init+0xb8/0xe0 | sp_init+0x6c/0x90 | sp_pci_probe+0x26e/0x590 | local_pci_probe+0x3f/0x90 | work_for_cpu_fn+0x11/0x20 | process_one_work+0x1ff/0x650 | worker_thread+0x1d4/0x3a0 | kthread+0xfe/0x130 | ret_from_fork+0x27/0x50
If any locking is required, a simple mutex will do it.
Cc: Gary R Hook gary.hook@amd.com Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Acked-by: Gary R Hook gary.hook@amd.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/crypto/ccp/ccp-debugfs.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
--- a/drivers/crypto/ccp/ccp-debugfs.c +++ b/drivers/crypto/ccp/ccp-debugfs.c @@ -278,7 +278,7 @@ static const struct file_operations ccp_ };
static struct dentry *ccp_debugfs_dir; -static DEFINE_RWLOCK(ccp_debugfs_lock); +static DEFINE_MUTEX(ccp_debugfs_lock);
#define MAX_NAME_LEN 20
@@ -290,16 +290,15 @@ void ccp5_debugfs_setup(struct ccp_devic struct dentry *debugfs_stats; struct dentry *debugfs_q_instance; struct dentry *debugfs_q_stats; - unsigned long flags; int i;
if (!debugfs_initialized()) return;
- write_lock_irqsave(&ccp_debugfs_lock, flags); + mutex_lock(&ccp_debugfs_lock); if (!ccp_debugfs_dir) ccp_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL); - write_unlock_irqrestore(&ccp_debugfs_lock, flags); + mutex_unlock(&ccp_debugfs_lock); if (!ccp_debugfs_dir) return;