Patch "iommu/vt-d: avoid invalid memory access via node_online(NUMA_NO_NODE)" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iommu/vt-d: avoid invalid memory access via node_online(NUMA_NO_NODE)

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iommu-vt-d-avoid-invalid-memory-access-via-node_onli.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 538e6fd1e59662975ef67b348de758020c8f31ab
Author: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
Date:   Tue Jul 12 17:38:36 2022 +0200

    iommu/vt-d: avoid invalid memory access via node_online(NUMA_NO_NODE)
    
    [ Upstream commit b0b0b77ea611e3088e9523e60860f4f41b62b235 ]
    
    KASAN reports:
    
    [ 4.668325][ T0] BUG: KASAN: wild-memory-access in dmar_parse_one_rhsa (arch/x86/include/asm/bitops.h:214 arch/x86/include/asm/bitops.h:226 include/asm-generic/bitops/instrumented-non-atomic.h:142 include/linux/nodemask.h:415 drivers/iommu/intel/dmar.c:497)
    [    4.676149][    T0] Read of size 8 at addr 1fffffff85115558 by task swapper/0/0
    [    4.683454][    T0]
    [    4.685638][    T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc3-00004-g0e862838f290 #1
    [    4.694331][    T0] Hardware name: Supermicro SYS-5018D-FN4T/X10SDV-8C-TLN4F, BIOS 1.1 03/02/2016
    [    4.703196][    T0] Call Trace:
    [    4.706334][    T0]  <TASK>
    [ 4.709133][ T0] ? dmar_parse_one_rhsa (arch/x86/include/asm/bitops.h:214 arch/x86/include/asm/bitops.h:226 include/asm-generic/bitops/instrumented-non-atomic.h:142 include/linux/nodemask.h:415 drivers/iommu/intel/dmar.c:497)
    
    after converting the type of the first argument (@nr, bit number)
    of arch_test_bit() from `long` to `unsigned long`[0].
    
    Under certain conditions (for example, when ACPI NUMA is disabled
    via command line), pxm_to_node() can return %NUMA_NO_NODE (-1).
    It is valid 'magic' number of NUMA node, but not valid bit number
    to use in bitops.
    node_online() eventually descends to test_bit() without checking
    for the input, assuming it's on caller side (which might be good
    for perf-critical tasks). There, -1 becomes %ULONG_MAX which leads
    to an insane array index when calculating bit position in memory.
    
    For now, add an explicit check for @node being not %NUMA_NO_NODE
    before calling test_bit(). The actual logics didn't change here
    at all.
    
    [0] https://github.com/norov/linux/commit/0e862838f290147ea9c16db852d8d494b552d38d
    
    Fixes: ee34b32d8c29 ("dmar: support for parsing Remapping Hardware Static Affinity structure")
    Cc: stable@xxxxxxxxxxxxxxx # 2.6.33+
    Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
    Signed-off-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
    Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
    Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
    Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 3d9cb711e87b..f026bd269cb0 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -497,7 +497,7 @@ static int dmar_parse_one_rhsa(struct acpi_dmar_header *header, void *arg)
 		if (drhd->reg_base_addr == rhsa->base_address) {
 			int node = pxm_to_node(rhsa->proximity_domain);
 
-			if (!node_online(node))
+			if (node != NUMA_NO_NODE && !node_online(node))
 				node = NUMA_NO_NODE;
 			drhd->iommu->node = node;
 			return 0;