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mmc: block: reject invalid perdev_minors before division

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The mmcblk.perdev_minors module parameter is parsed as a signed int and
is used during mmc_blk_init() to compute the number of supported block
devices.

Passing perdev_minors=0 makes the init path divide by zero when it
computes max_devices. Negative values are invalid as well and would make
max_devices negative before it is later used as an IDA limit.

Reject non-positive perdev_minors values before registering any mmcblk
resources.

Signed-off-by: Xu Rao <raoxu@uniontech.com>
Signed-off-by: Ulf Hansson <ulfh@kernel.org>
This commit is contained in:
Xu Rao 2026-07-06 17:25:00 +08:00 committed by Ulf Hansson
parent df92d47b3a
commit 5253aee00a
1 changed files with 5 additions and 0 deletions
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5
drivers/mmc/core/block.c
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@ -3337,6 +3337,11 @@ static int __init mmc_blk_init(void)
{
int res;
if (perdev_minors <= 0) {
pr_err("mmcblk: invalid minors per device: %d\n", perdev_minors);
return -EINVAL;
}
res = bus_register(&mmc_rpmb_bus_type);
if (res < 0) {
pr_err("mmcblk: could not register RPMB bus type\n");