diff options
author | Junhao He <hejunhao3@huawei.com> | 2023-11-14 16:33:43 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-13 20:45:28 +0300 |
commit | ace850bd8600328f8f56e41db88d7b232ab939d4 (patch) | |
tree | 72c5c758e1af270be011efa0389637fdc8ad8177 /drivers/hwtracing/coresight/ultrasoc-smb.c | |
parent | 359d3fbcbc099430ca3f35a696e298e9c2d9e9ba (diff) | |
download | linux-ace850bd8600328f8f56e41db88d7b232ab939d4.tar.xz |
coresight: ultrasoc-smb: Fix sleep while close preempt in enable_smb
[ Upstream commit b8411287aef4a994eff0c68f5597910c4194dfe3 ]
When we to enable the SMB by perf, the perf sched will call perf_ctx_lock()
to close system preempt in event_function_call(). But SMB::enable_smb() use
mutex to lock the critical section, which may sleep.
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 153023, name: perf
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48
softirqs last enabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 2 PID: 153023 Comm: perf Kdump: loaded Tainted: G W O 6.5.0-rc4+ #1
Call trace:
...
__mutex_lock+0xbc/0xa70
mutex_lock_nested+0x34/0x48
smb_update_buffer+0x58/0x360 [ultrasoc_smb]
etm_event_stop+0x204/0x2d8 [coresight]
etm_event_del+0x1c/0x30 [coresight]
event_sched_out+0x17c/0x3b8
group_sched_out.part.0+0x5c/0x208
__perf_event_disable+0x15c/0x210
event_function+0xe0/0x230
remote_function+0xb4/0xe8
generic_exec_single+0x160/0x268
smp_call_function_single+0x20c/0x2a0
event_function_call+0x20c/0x220
_perf_event_disable+0x5c/0x90
perf_event_for_each_child+0x58/0xc0
_perf_ioctl+0x34c/0x1250
perf_ioctl+0x64/0x98
...
Use spinlock to replace mutex to control driver data access to one at a
time. The function copy_to_user() may sleep, it cannot be in a spinlock
context, so we can't simply replace it in smb_read(). But we can ensure
that only one user gets the SMB device fd by smb_open(), so remove the
locks from smb_read() and buffer synchronization is guaranteed by the user.
Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-2-hejunhao3@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hwtracing/coresight/ultrasoc-smb.c')
-rw-r--r-- | drivers/hwtracing/coresight/ultrasoc-smb.c | 35 |
1 files changed, 14 insertions, 21 deletions
diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c b/drivers/hwtracing/coresight/ultrasoc-smb.c index e9a32a97fbee..0a0fe9fcc57f 100644 --- a/drivers/hwtracing/coresight/ultrasoc-smb.c +++ b/drivers/hwtracing/coresight/ultrasoc-smb.c @@ -99,7 +99,7 @@ static int smb_open(struct inode *inode, struct file *file) struct smb_drv_data, miscdev); int ret = 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); if (drvdata->reading) { ret = -EBUSY; @@ -115,7 +115,7 @@ static int smb_open(struct inode *inode, struct file *file) drvdata->reading = true; out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return ret; } @@ -132,10 +132,8 @@ static ssize_t smb_read(struct file *file, char __user *data, size_t len, if (!len) return 0; - mutex_lock(&drvdata->mutex); - if (!sdb->data_size) - goto out; + return 0; to_copy = min(sdb->data_size, len); @@ -145,20 +143,15 @@ static ssize_t smb_read(struct file *file, char __user *data, size_t len, if (copy_to_user(data, sdb->buf_base + sdb->buf_rdptr, to_copy)) { dev_dbg(dev, "Failed to copy data to user\n"); - to_copy = -EFAULT; - goto out; + return -EFAULT; } *ppos += to_copy; - smb_update_read_ptr(drvdata, to_copy); - - dev_dbg(dev, "%zu bytes copied\n", to_copy); -out: if (!sdb->data_size) smb_reset_buffer(drvdata); - mutex_unlock(&drvdata->mutex); + dev_dbg(dev, "%zu bytes copied\n", to_copy); return to_copy; } @@ -167,9 +160,9 @@ static int smb_release(struct inode *inode, struct file *file) struct smb_drv_data *drvdata = container_of(file->private_data, struct smb_drv_data, miscdev); - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); drvdata->reading = false; - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return 0; } @@ -262,7 +255,7 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode, struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent); int ret = 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); /* Do nothing, the trace data is reading by other interface now */ if (drvdata->reading) { @@ -294,7 +287,7 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode, dev_dbg(&csdev->dev, "Ultrasoc SMB enabled\n"); out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return ret; } @@ -304,7 +297,7 @@ static int smb_disable(struct coresight_device *csdev) struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent); int ret = 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); if (drvdata->reading) { ret = -EBUSY; @@ -327,7 +320,7 @@ static int smb_disable(struct coresight_device *csdev) dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n"); out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return ret; } @@ -408,7 +401,7 @@ static unsigned long smb_update_buffer(struct coresight_device *csdev, if (!buf) return 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); /* Don't do anything if another tracer is using this sink. */ if (atomic_read(&csdev->refcnt) != 1) @@ -432,7 +425,7 @@ static unsigned long smb_update_buffer(struct coresight_device *csdev, if (!buf->snapshot && lost) perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return data_size; } @@ -590,7 +583,7 @@ static int smb_probe(struct platform_device *pdev) return ret; } - mutex_init(&drvdata->mutex); + spin_lock_init(&drvdata->spinlock); drvdata->pid = -1; ret = smb_register_sink(pdev, drvdata); |