+ mm-vmalloc-fix-the-unchecked-dereference-warning-in-vread_iter.patch added to mm-hotfixes-unstable branch

+ mm-vmalloc-fix-the-unchecked-dereference-warning-in-vread_iter.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/vmalloc: fix the unchecked dereference warning in vread_iter()
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-vmalloc-fix-the-unchecked-dereference-warning-in-vread_iter.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-fix-the-unchecked-dereference-warning-in-vread_iter.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Baoquan He <bhe@redhat.com>
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
=====================

So add checking on whether 'vm' is not null when dereferencing it in
vread_iter(). This mutes smatch complaint.

Link: https://lkml.kernel.org/r/ZS/2k6DIMd0tZRgK@MiWiFi-R3L-srv
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202310171600.WCrsOwFj-lkp@intel.com/
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Philip Li <philip.li@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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@redhat.com are

mm-vmalloc-fix-the-unchecked-dereference-warning-in-vread_iter.patch