From: Carlos Llamas Date: Tue, 27 Jan 2026 23:55:10 +0000 (+0000) Subject: rust_binderfs: fix ida_alloc_max() upper bound X-Git-Tag: v6.19~4^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d6ba734814266bbf7ee01f9030436597116805f3;p=thirdparty%2Fkernel%2Flinux.git rust_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: eafedbc7c050 ("rust_binder: add Rust Binder driver") Reported-by: kernel test robot Closes: https://lore.kernel.org/r/202512181203.IOv6IChH-lkp@intel.com/ Signed-off-by: Carlos Llamas Reviewed-by: Alice Ryhl Link: https://patch.msgid.link/20260127235545.2307876-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/android/binder/rust_binderfs.c b/drivers/android/binder/rust_binderfs.c index c69026df775c..88374b31ab7c 100644 --- a/drivers/android/binder/rust_binderfs.c +++ b/drivers/android/binder/rust_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; @@ -405,8 +405,8 @@ 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) {