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author | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2018-02-12 23:47:45 +0100 |
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committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2018-03-01 10:49:29 +0100 |
commit | 53d29e0a3afe0567db9e4360e8523b092eb2d4e4 (patch) | |
tree | dacc451b5910022aae5fb25acf00a59672f6d19f /Documentation/unaligned-memory-access.txt | |
parent | rtc: ds1553: make alarms useful (diff) | |
download | linux-53d29e0a3afe0567db9e4360e8523b092eb2d4e4.tar.xz linux-53d29e0a3afe0567db9e4360e8523b092eb2d4e4.zip |
rtc: cmos: fix possible race condition
The probe function is not allowed to fail after registering the RTC because
the following may happen:
CPU0: CPU1:
sys_load_module()
do_init_module()
do_one_initcall()
cmos_do_probe()
rtc_device_register()
__register_chrdev()
cdev->owner = struct module*
open("/dev/rtc0")
rtc_device_unregister()
module_put()
free_module()
module_free(mod->module_core)
/* struct module *module is now
freed */
chrdev_open()
spin_lock(cdev_lock)
cdev_get()
try_module_get()
module_is_live()
/* dereferences already
freed struct module* */
Switch to devm_rtc_allocate_device/rtc_register_device to register the rtc
as late as possible.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'Documentation/unaligned-memory-access.txt')
0 files changed, 0 insertions, 0 deletions