The quilt patch titled Subject: mm/vmalloc: fix the unchecked dereference warning in vread_iter() has been removed from the -mm tree. Its filename was mm-vmalloc-fix-the-unchecked-dereference-warning-in-vread_iter.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Baoquan He <bhe@xxxxxxxxxx> Subject: mm/vmalloc: fix the unchecked dereference warning in vread_iter() Date: Wed, 18 Oct 2023 22:50:14 +0800 LKP reported smatch warning as below: =================== smatch warnings: mm/vmalloc.c:3689 vread_iter() error: we previously assumed 'vm' could be null (see line 3667) ...... 06c8994626d1b7 @3667 size = vm ? get_vm_area_size(vm) : va_size(va); ...... 06c8994626d1b7 @3689 else if (!(vm->flags & VM_IOREMAP)) ^^^^^^^^^ Unchecked dereference ===================== This is not a runtime bug because the possible null 'vm' in the pointed place could only happen when flags == VMAP_BLOCK. However, the case 'flags == VMAP_BLOCK' should never happen and has been detected with WARN_ON. Please check vm_map_ram() implementation and the earlier checking in vread_iter() at below: ~~~~~~~~~~~~~~~~~~~~~~~~~~ /* * VMAP_BLOCK indicates a sub-type of vm_map_ram area, need * be set together with VMAP_RAM. */ WARN_ON(flags == VMAP_BLOCK); if (!vm && !flags) continue; ~~~~~~~~~~~~~~~~~~~~~~~~~~ So add checking on whether 'vm' could be null when dereferencing it in vread_iter(). This mutes smatch complaint. Link: https://lkml.kernel.org/r/ZTCURc8ZQE+KrTvS@MiWiFi-R3L-srv Link: https://lkml.kernel.org/r/ZS/2k6DIMd0tZRgK@MiWiFi-R3L-srv Signed-off-by: Baoquan He <bhe@xxxxxxxxxx> Reported-by: kernel test robot <lkp@xxxxxxxxx> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Closes: https://lore.kernel.org/r/202310171600.WCrsOwFj-lkp@xxxxxxxxx/ Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx> Cc: Philip Li <philip.li@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/vmalloc.c~mm-vmalloc-fix-the-unchecked-dereference-warning-in-vread_iter +++ a/mm/vmalloc.c @@ -3809,7 +3809,7 @@ long vread_iter(struct iov_iter *iter, c if (flags & VMAP_RAM) copied = vmap_ram_vread_iter(iter, addr, n, flags); - else if (!(vm->flags & VM_IOREMAP)) + else if (!(vm && (vm->flags & VM_IOREMAP))) copied = aligned_vread_iter(iter, addr, n); else /* IOREMAP area is treated as memory hole */ copied = zero_iter(iter, n); _ Patches currently in -mm which might be from bhe@xxxxxxxxxx are