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Code Issues Releases Activity

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:
Hans Petter Selasky 2017-10-13 14:14:46 +00:00
parent 6e309d75d2
commit 627ac5b4e3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=324597
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); return (error);
} }
#define LINUX_POLL_TABLE_NORMAL ((poll_table *)1)
static int static int
linux_dev_poll(struct cdev *dev, int events, struct thread *td) 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; filp->f_flags = file->f_flag;
linux_set_current(td); linux_set_current(td);
if (filp->f_op->poll != NULL) 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 else
revents = 0; 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, [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)) { switch (linux_poll_wakeup_state(&filp->f_wait_queue.state, state)) {
case LINUX_FWQ_STATE_INIT: 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 = (struct linux_file *)file->f_data;
filp->f_flags = file->f_flag; filp->f_flags = file->f_flag;
linux_set_current(td); linux_set_current(td);
if (filp->f_op->poll != NULL) { if (filp->f_op->poll != NULL)
selrecord(td, &filp->f_selinfo); revents = filp->f_op->poll(filp, LINUX_POLL_TABLE_NORMAL) & events;
revents = filp->f_op->poll(filp, NULL) & events; else
} else
revents = 0; revents = 0;
return (revents); return (revents);