diff options
| author | Thadeu Lima de Souza Cascardo <cascardo@igalia.com> | 2025-03-17 10:59:55 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-02 07:59:10 +0200 |
| commit | 3670dee37657ea0c812161c838e7fde99471c846 (patch) | |
| tree | b69ac2b49461d6e406c9521d75cb4d832a4a79a7 | |
| parent | 26df754de545d4a3631542fc983c294cdfb8bf86 (diff) | |
char: misc: register chrdev region with all possible minors
commit c876be906ce7e518d9ef9926478669c151999e69 upstream.
register_chrdev will only register the first 256 minors of a major chrdev.
That means that dynamically allocated misc devices with minor above 255
will fail to open with -ENXIO.
This was found by kernel test robot when testing a different change that
makes all dynamically allocated minors be above 255. This has, however,
been separately tested by creating 256 serio_raw devices with the help of
userio driver.
Ever since allowing misc devices with minors above 128, this has been
possible.
Fix it by registering all minor numbers from 0 to MINORMASK + 1 for
MISC_MAJOR.
Reported-by: kernel test robot <oliver.sang@intel.com>
Cc: stable <stable@kernel.org>
Closes: https://lore.kernel.org/oe-lkp/202503171507.6c8093d0-lkp@intel.com
Fixes: ab760791c0cf ("char: misc: Increase the maximum number of dynamic misc devices to 1048448")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Tested-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Link: https://lore.kernel.org/r/20250317-misc-chrdev-v1-1-6cd05da11aef@igalia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/misc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/misc.c b/drivers/char/misc.c index f7dd455dd0dd..dda466f9181a 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -315,7 +315,7 @@ static int __init misc_init(void) goto fail_remove; err = -EIO; - if (register_chrdev(MISC_MAJOR, "misc", &misc_fops)) + if (__register_chrdev(MISC_MAJOR, 0, MINORMASK + 1, "misc", &misc_fops)) goto fail_printk; return 0; |