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Don't call selrecord() outside the select system call in the LinuxKPI, because

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then td->td_sel is NULL and this will result in a segfault inside selrecord().
This happens when only using kqueue() to poll for read and write events.
If select() and kqueue() is mixed there won't be a segfault.

Reported by:	Johannes Lundberg
MFC after:	1 week
Sponsored by:	Mellanox Technologies
This commit is contained in:
hselasky 2017-10-13 14:14:46 +00:00
parent 951751c6c6
commit 573665c410
1 changed files with 9 additions and 6 deletions
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15
sys/compat/linuxkpi/common/src/linux_compat.c
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@ -1021,6 +1021,8 @@ linux_dev_write(struct cdev *dev, struct uio *uio, int ioflag)
return (error);
}
#define LINUX_POLL_TABLE_NORMAL ((poll_table *)1)
static int
linux_dev_poll(struct cdev *dev, int events, struct thread *td)
{
@ -1037,7 +1039,7 @@ linux_dev_poll(struct cdev *dev, int events, struct thread *td)
filp->f_flags = file->f_flag;
linux_set_current(td);
if (filp->f_op->poll != NULL)
revents = filp->f_op->poll(filp, NULL) & events;
revents = filp->f_op->poll(filp, LINUX_POLL_TABLE_NORMAL) & events;
else
revents = 0;
@ -1094,7 +1096,9 @@ linux_poll_wait(struct linux_file *filp, wait_queue_head_t *wqh, poll_table *p)
[LINUX_FWQ_STATE_READY] = LINUX_FWQ_STATE_QUEUED,
};
selrecord(curthread, &filp->f_selinfo);
/* check if we are called inside the select system call */
if (p == LINUX_POLL_TABLE_NORMAL)
selrecord(curthread, &filp->f_selinfo);
switch (linux_poll_wakeup_state(&filp->f_wait_queue.state, state)) {
case LINUX_FWQ_STATE_INIT:
@ -1438,10 +1442,9 @@ linux_file_poll(struct file *file, int events, struct ucred *active_cred,
filp = (struct linux_file *)file->f_data;
filp->f_flags = file->f_flag;
linux_set_current(td);
if (filp->f_op->poll != NULL) {
selrecord(td, &filp->f_selinfo);
revents = filp->f_op->poll(filp, NULL) & events;
} else
if (filp->f_op->poll != NULL)
revents = filp->f_op->poll(filp, LINUX_POLL_TABLE_NORMAL) & events;
else
revents = 0;
return (revents);