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Message-ID: <20250803072044.572733-8-ysk@kzalloc.com>
Date: Sun, 3 Aug 2025 07:20:47 +0000
From: Yunseong Kim <ysk@...lloc.com>
To: Dmitry Vyukov <dvyukov@...gle.com>,
Andrey Konovalov <andreyknvl@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
Byungchul Park <byungchul@...com>,
max.byungchul.park@...il.com,
Yeoreum Yun <yeoreum.yun@....com>,
ppbuk5246@...il.com,
linux-usb@...r.kernel.org,
linux-rt-devel@...ts.linux.dev,
syzkaller@...glegroups.com,
linux-kernel@...r.kernel.org,
stable@...r.kernel.org,
Yunseong Kim <ysk@...lloc.com>
Subject: [PATCH 3/4] kcov: Separate KCOV_REMOTE_ENABLE ioctl helper function
kcov_ioctl() entry point is updated to dispatch commands to the
appropriate helper function, calling kcov_ioctl_locked_remote_enabled()
for the remote enable case and the now-simplified kcov_ioctl_locked() for
KCOV_ENABLE and KCOV_DISABLE commands.
Signed-off-by: Yunseong Kim <ysk@...lloc.com>
---
kernel/kcov.c | 142 +++++++++++++++++++++++++++-----------------------
1 file changed, 77 insertions(+), 65 deletions(-)
diff --git a/kernel/kcov.c b/kernel/kcov.c
index faad3b288ca7..1e7f08ddf0e8 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -579,15 +579,81 @@ static inline bool kcov_check_handle(u64 handle, bool common_valid,
return false;
}
-static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
- unsigned long arg)
+static int kcov_ioctl_locked_remote_enabled(struct kcov *kcov,
+ unsigned int cmd, unsigned long arg)
{
struct task_struct *t;
- unsigned long flags, unused;
+ unsigned long flags;
int mode, i;
struct kcov_remote_arg *remote_arg;
struct kcov_remote *remote;
+ if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
+ return -EINVAL;
+ t = current;
+ if (kcov->t != NULL || t->kcov != NULL)
+ return -EBUSY;
+ remote_arg = (struct kcov_remote_arg *)arg;
+ mode = kcov_get_mode(remote_arg->trace_mode);
+ if (mode < 0)
+ return mode;
+ if ((unsigned long)remote_arg->area_size >
+ LONG_MAX / sizeof(unsigned long))
+ return -EINVAL;
+ kcov->mode = mode;
+ t->kcov = kcov;
+ t->kcov_mode = KCOV_MODE_REMOTE;
+ kcov->t = t;
+ kcov->remote = true;
+ kcov->remote_size = remote_arg->area_size;
+ raw_spin_lock_irqsave(&kcov_remote_lock, flags);
+ for (i = 0; i < remote_arg->num_handles; i++) {
+ if (!kcov_check_handle(remote_arg->handles[i],
+ false, true, false)) {
+ raw_spin_unlock_irqrestore(&kcov_remote_lock,
+ flags);
+ kcov_disable(t, kcov);
+ return -EINVAL;
+ }
+ remote = kcov_remote_add(kcov, remote_arg->handles[i]);
+ if (IS_ERR(remote)) {
+ raw_spin_unlock_irqrestore(&kcov_remote_lock,
+ flags);
+ kcov_disable(t, kcov);
+ return PTR_ERR(remote);
+ }
+ }
+ if (remote_arg->common_handle) {
+ if (!kcov_check_handle(remote_arg->common_handle,
+ true, false, false)) {
+ raw_spin_unlock_irqrestore(&kcov_remote_lock,
+ flags);
+ kcov_disable(t, kcov);
+ return -EINVAL;
+ }
+ remote = kcov_remote_add(kcov,
+ remote_arg->common_handle);
+ if (IS_ERR(remote)) {
+ raw_spin_unlock_irqrestore(&kcov_remote_lock,
+ flags);
+ kcov_disable(t, kcov);
+ return PTR_ERR(remote);
+ }
+ t->kcov_handle = remote_arg->common_handle;
+ }
+ raw_spin_unlock_irqrestore(&kcov_remote_lock, flags);
+ /* Put either in kcov_task_exit() or in KCOV_DISABLE. */
+ kcov_get(kcov);
+ return 0;
+}
+
+static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
+ unsigned long arg)
+{
+ struct task_struct *t;
+ unsigned long unused;
+ int mode;
+
switch (cmd) {
case KCOV_ENABLE:
/*
@@ -624,64 +690,6 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
kcov_disable(t, kcov);
kcov_put(kcov);
return 0;
- case KCOV_REMOTE_ENABLE:
- if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
- return -EINVAL;
- t = current;
- if (kcov->t != NULL || t->kcov != NULL)
- return -EBUSY;
- remote_arg = (struct kcov_remote_arg *)arg;
- mode = kcov_get_mode(remote_arg->trace_mode);
- if (mode < 0)
- return mode;
- if ((unsigned long)remote_arg->area_size >
- LONG_MAX / sizeof(unsigned long))
- return -EINVAL;
- kcov->mode = mode;
- t->kcov = kcov;
- t->kcov_mode = KCOV_MODE_REMOTE;
- kcov->t = t;
- kcov->remote = true;
- kcov->remote_size = remote_arg->area_size;
- raw_spin_lock_irqsave(&kcov_remote_lock, flags);
- for (i = 0; i < remote_arg->num_handles; i++) {
- if (!kcov_check_handle(remote_arg->handles[i],
- false, true, false)) {
- raw_spin_unlock_irqrestore(&kcov_remote_lock,
- flags);
- kcov_disable(t, kcov);
- return -EINVAL;
- }
- remote = kcov_remote_add(kcov, remote_arg->handles[i]);
- if (IS_ERR(remote)) {
- raw_spin_unlock_irqrestore(&kcov_remote_lock,
- flags);
- kcov_disable(t, kcov);
- return PTR_ERR(remote);
- }
- }
- if (remote_arg->common_handle) {
- if (!kcov_check_handle(remote_arg->common_handle,
- true, false, false)) {
- raw_spin_unlock_irqrestore(&kcov_remote_lock,
- flags);
- kcov_disable(t, kcov);
- return -EINVAL;
- }
- remote = kcov_remote_add(kcov,
- remote_arg->common_handle);
- if (IS_ERR(remote)) {
- raw_spin_unlock_irqrestore(&kcov_remote_lock,
- flags);
- kcov_disable(t, kcov);
- return PTR_ERR(remote);
- }
- t->kcov_handle = remote_arg->common_handle;
- }
- raw_spin_unlock_irqrestore(&kcov_remote_lock, flags);
- /* Put either in kcov_task_exit() or in KCOV_DISABLE. */
- kcov_get(kcov);
- return 0;
default:
return -ENOTTY;
}
@@ -740,16 +748,20 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
return -EINVAL;
}
arg = (unsigned long)remote_arg;
- fallthrough;
+ raw_spin_lock_irqsave(&kcov->lock, flags);
+ res = kcov_ioctl_locked_remote_enabled(kcov, cmd, arg);
+ raw_spin_unlock_irqrestore(&kcov->lock, flags);
+ kfree(remote_arg);
+ return res;
default:
/*
- * All other commands can be normally executed under a spin lock, so we
- * obtain and release it here in order to simplify kcov_ioctl_locked().
+ * KCOV_ENABLE and KCOV_DISABLE commands can be normally executed under
+ * a raw spin lock, so we obtain and release it here in order to
+ * simplify kcov_ioctl_locked().
*/
raw_spin_lock_irqsave(&kcov->lock, flags);
res = kcov_ioctl_locked(kcov, cmd, arg);
raw_spin_unlock_irqrestore(&kcov->lock, flags);
- kfree(remote_arg);
return res;
}
}
--
2.50.0
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