From: Thadeu Lima de Souza Cascardo Date: Mon, 17 Mar 2025 13:59:55 +0000 (-0300) Subject: char: misc: register chrdev region with all possible minors X-Git-Tag: v6.15-rc4~23^2~7 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=c876be906ce7e518d9ef9926478669c151999e69;p=linux-block.git char: misc: register chrdev region with all possible minors 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 Cc: stable 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 Tested-by: Hou Wenlong Link: https://lore.kernel.org/r/20250317-misc-chrdev-v1-1-6cd05da11aef@igalia.com Signed-off-by: Greg Kroah-Hartman --- 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;