From: Yury Norov <yury.norov@xxxxxxxxx> Date: Mon, 11 Jul 2022 11:24:42 -0700 > On Mon, Jul 11, 2022 at 9:15 AM Alexander Lobakin > <alexandr.lobakin@xxxxxxxxx> wrote: > > > > From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > > Date: Fri, 8 Jul 2022 15:17:40 +0300 > > > >> On Thu, Jul 07, 2022 at 10:10:20PM +0800, kernel test robot wrote: > >>> > >>> (please be noted we reported > >>> "[bitops] 001bea109d: BUG:KASAN:wild-memory-access_in_dmar_parse_one_rhsa" > >>> on > >>> https://lore.kernel.org/all/YrnGLtDXAveqXGok@xsang-OptiPlex-9020/ > >>> now we noticed this commit has already been merged into linux-next/master, > >>> and the issue is still existing. report again FYI) > >>> > >>> Greeting, > >>> > >>> FYI, we noticed the following commit (built with gcc-11): > >>> > >>> commit: 0e862838f290147ea9c16db852d8d494b552d38d ("bitops: unify non-atomic bitops prototypes across architectures") > >>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master > >>> > >>> in testcase: xfstests > >>> version: xfstests-x86_64-c1144bf-1_20220627 > >>> with following parameters: > >>> > >>> disk: 2pmem > >>> fs: ext4 > >>> test: ext4-dax > >>> ucode: 0x700001c > >>> > >>> test-description: xfstests is a regression test suite for xfs and other files ystems. > >>> test-url: git://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git > >>> > >>> > >>> on test machine: 16 threads 1 sockets Intel(R) Xeon(R) CPU D-1541 @ 2.10GHz with 48G memory > >>> > >>> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > >>> > >>> > >>> > >>> If you fix the issue, kindly add following tag > >>> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> > >>> > >>> > >>> [ 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) > >>> [ 4.714272][ T0] dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1)) > >>> [ 4.718632][ T0] kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:493) > >>> [ 4.722903][ 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) > >>> [ 4.728042][ T0] kasan_check_range (mm/kasan/generic.c:190) > >>> [ 4.732750][ 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) > >>> [ 4.737715][ T0] dmar_walk_remapping_entries (drivers/iommu/intel/dmar.c:609) > >>> [ 4.743375][ T0] parse_dmar_table (drivers/iommu/intel/dmar.c:671) > >>> [ 4.748079][ T0] ? dmar_table_detect (drivers/iommu/intel/dmar.c:633) > >>> [ 4.752872][ T0] ? dmar_free_dev_scope (drivers/iommu/intel/dmar.c:408) > >>> [ 4.758010][ T0] ? init_dmars (drivers/iommu/intel/iommu.c:3359) > >>> [ 4.762370][ T0] ? iommu_resume (drivers/iommu/intel/iommu.c:3419) > >>> [ 4.766903][ T0] ? dmar_walk_dsm_resource+0x300/0x300 > >>> [ 4.772909][ T0] ? dmar_acpi_insert_dev_scope (drivers/iommu/intel/dmar.c:466) > >>> [ 4.778655][ T0] ? dmar_check_one_atsr (drivers/iommu/intel/iommu.c:3521) > >>> [ 4.783795][ T0] dmar_table_init (drivers/iommu/intel/dmar.c:846) > >>> [ 4.788239][ T0] intel_prepare_irq_remapping (drivers/iommu/intel/irq_remapping.c:742) > >>> [ 4.793811][ T0] irq_remapping_prepare (drivers/iommu/irq_remapping.c:102) > >>> [ 4.798778][ T0] enable_IR_x2apic (arch/x86/kernel/apic/apic.c:1928) > >>> [ 4.803395][ T0] default_setup_apic_routing (arch/x86/kernel/apic/probe_64.c:25 (discriminator 1)) > >>> [ 4.808883][ T0] apic_intr_mode_init (arch/x86/kernel/apic/apic.c:1446) > >>> [ 4.813761][ T0] x86_late_time_init (arch/x86/kernel/time.c:101) > >>> [ 4.818467][ T0] start_kernel (init/main.c:1101) > >>> [ 4.822827][ T0] secondary_startup_64_no_verify (arch/x86/kernel/head_64.S:358) > >> > >> Seems like related to nodemask APIs. > > > > It points to arch_test_bit() (node_online() -> test_bit()), > > converted from a macro to a function, more precisely, to > > variable_test_bit(), which I didn't touch. > > > > ...oh ok I got it! > > > > pxm_to_node() can return %NUMA_NO_NODE which equals to -1. The > > mentioned commit converts the macro to the function which now takes > > `unsigned long` as @nr (bit number). So I guess it gets converted to > > %ULONG_MAX - 1. > > > > Now the question is: what should a bitop do if we have negative bit > > number? Because there are 2 solutions: > > > > 1. (I prefer it) A caller must check that bitop arguments are valid. > > UB for negative (== too big) bit numbers. > > dmar_parse_one_rhsa() must be fixed so that it will check return > > value of pxm_to_node(): > > > > int node = pxm_to_node(rhsa->proximity_domain); > > > > - if (!node_online(node)) > > + if (node != NUMA_NO_NODE && !node_online(node)) > > Would it make sense to check it inside node_online()? Probably as a more global improvement. I believe it's used very often on hotpath, where it's known it can't be < 0, so for now I'd pick the check inside this function. > > > node = NUMA_NO_NODE; > > > > 2. My code is broken, I shouldn't change `long` to `unsigned long` > > or should change it for {constant,variable}_test_bit() as well > > or do something else and let it behave as it was previously > > (it wasn't crashing probably due to a good luck or...). > > This is definitely a NUMA problem. Bitmap has 2 kernel-wide users: > cpumasks and numa nodes. Both use negative indexes for their > reasons, which is dangerous, as we can see from here, because > bitmaps don't support them and don't handle it properly... > > Can you please send a fix dmar_parse_one_rhsa() as you suggested, > so that I'll add the fix before the beginning of next merge window? Sure, sending in a couple hours. I guess it would be nice to get Acked-by from a maintainer of that subsys (if it won't take too long). > > Regarding a general path, this is what I'm thinking on (for a while): > - #define NUMA_NO_NODE MAX_NUMNODES; > - stronger typechecking, like you did in your series; > - introduce CONFIG_DEBUG_BITMAP to catch bad arguments > on-the-fly; > > I'm working on DEBUG_BITMAP, hopefully submit it for next merge > cycle. I like the idea! > > Thanks, > Yury Thanks, Olek
