Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-25 20:32:22 +00:00
Code Issues Packages Projects Releases Wiki Activity

drivers: char: tlclk.c: Avoid data race between init and interrupt handler

Browse Source 
After registering character device the file operation callbacks can be
called. The open callback registers interrupt handler.
Therefore interrupt handler can execute in parallel with rest of the init
function. To avoid such data race initialize telclk_interrupt variable
and struct alarm_events before registering character device.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Link: https://lore.kernel.org/r/20200417153451.1551-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Madhuparna Bhowmik 2020-04-17 21:04:51 +05:30 committed by Greg Kroah-Hartman
parent c18c1f1035
commit 44b8fb6eaa
1 changed files with 11 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/char/tlclk.c
View File

@ -777,18 +777,22 @@ static int __init tlclk_init(void)
{
int ret;
ret = register_chrdev(tlclk_major, "telco_clock", &tlclk_fops);
if (ret < 0) {
printk(KERN_ERR "tlclk: can't get major %d.\n", tlclk_major);
return ret;
}
tlclk_major = ret;
telclk_interrupt = (inb(TLCLK_REG7) & 0x0f);
alarm_events = kzalloc( sizeof(struct tlclk_alarms), GFP_KERNEL);
if (!alarm_events) {
ret = -ENOMEM;
goto out1;
}
ret = register_chrdev(tlclk_major, "telco_clock", &tlclk_fops);
if (ret < 0) {
printk(KERN_ERR "tlclk: can't get major %d.\n", tlclk_major);
kfree(alarm_events);
return ret;
}
tlclk_major = ret;
/* Read telecom clock IRQ number (Set by BIOS) */
if (!request_region(TLCLK_BASE, 8, "telco_clock")) {
printk(KERN_ERR "tlclk: request_region 0x%X failed.\n",
@ -796,7 +800,6 @@ static int __init tlclk_init(void)
ret = -EBUSY;
goto out2;
}
telclk_interrupt = (inb(TLCLK_REG7) & 0x0f);
if (0x0F == telclk_interrupt ) { /* not MCPBL0010 ? */
printk(KERN_ERR "telclk_interrupt = 0x%x non-mcpbl0010 hw.\n",
@ -837,8 +840,8 @@ out3:
release_region(TLCLK_BASE, 8);
out2:
kfree(alarm_events);
out1:
unregister_chrdev(tlclk_major, "telco_clock");
out1:
return ret;
}