From ec4ddc90d201d09ef4e4bef8a2c6d9624525ad68 Mon Sep 17 00:00:00 2001 From: Carlos Llamas Date: Tue, 27 Jan 2026 23:55:11 +0000 Subject: [PATCH] binderfs: fix ida_alloc_max() upper bound The 'max' argument of ida_alloc_max() takes the maximum valid ID and not the "count". Using an ID of BINDERFS_MAX_MINOR (1 << 20) for dev->minor would exceed the limits of minor numbers (20-bits). Fix this off-by-one error by subtracting 1 from the 'max'. Cc: stable@vger.kernel.org Fixes: 3ad20fe393b3 ("binder: implement binderfs") Signed-off-by: Carlos Llamas Link: https://patch.msgid.link/20260127235545.2307876-2-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/android/binderfs.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c index b46bcb91072de..9f8a18c88d66e 100644 --- a/drivers/android/binderfs.c +++ b/drivers/android/binderfs.c @@ -132,8 +132,8 @@ static int binderfs_binder_device_create(struct inode *ref_inode, mutex_lock(&binderfs_minors_mutex); if (++info->device_count <= info->mount_opts.max) minor = ida_alloc_max(&binderfs_minors, - use_reserve ? BINDERFS_MAX_MINOR : - BINDERFS_MAX_MINOR_CAPPED, + use_reserve ? BINDERFS_MAX_MINOR - 1 : + BINDERFS_MAX_MINOR_CAPPED - 1, GFP_KERNEL); else minor = -ENOSPC; @@ -408,8 +408,8 @@ static int binderfs_binder_ctl_create(struct super_block *sb) /* Reserve a new minor number for the new device. */ mutex_lock(&binderfs_minors_mutex); minor = ida_alloc_max(&binderfs_minors, - use_reserve ? BINDERFS_MAX_MINOR : - BINDERFS_MAX_MINOR_CAPPED, + use_reserve ? BINDERFS_MAX_MINOR - 1 : + BINDERFS_MAX_MINOR_CAPPED - 1, GFP_KERNEL); mutex_unlock(&binderfs_minors_mutex); if (minor < 0) { -- 2.47.3