From 465ba08bb53796b24dceca0d2ccde5a0e2630a2b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jean-S=C3=A9bastien=20P=C3=A9dron?= Date: Tue, 3 Feb 2026 13:04:58 +0100 Subject: [PATCH] vm_phys: Check `RB_FIND()` return value in case it is NULL When trying to unregister a fictitious range in `vm_phys_fictitious_unreg_range()`, the function checks the properties of the looked up segment, but it does not check if a segment was found in the first place. This can happen with the amdgpu DRM driver which could call `vm_phys_fictitious_unreg_range()` without a fictitious range registered if the initialisation of the driver failed (for example because firmwares are unavailable). The code in the DRM driver was improved to avoid that, but `vm_phys_fictitious_unreg_range()` should still check the return value of `RB_FIND()` before trying to dereference the segment pointer and panic with a page fault. Reviewed by: emaste Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D55076 --- sys/vm/vm_phys.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c index ba16ae55109..1737020436c 100644 --- a/sys/vm/vm_phys.c +++ b/sys/vm/vm_phys.c @@ -1213,7 +1213,7 @@ vm_phys_fictitious_unreg_range(vm_paddr_t start, vm_paddr_t end) rw_wlock(&vm_phys_fictitious_reg_lock); seg = RB_FIND(fict_tree, &vm_phys_fictitious_tree, &tmp); - if (seg->start != start || seg->end != end) { + if (seg == NULL || seg->start != start || seg->end != end) { rw_wunlock(&vm_phys_fictitious_reg_lock); panic( "Unregistering not registered fictitious range [%#jx:%#jx]",