[PATCH 0/5 v16] KASan for Arm
Ard Biesheuvel
ardb at kernel.org
Fri Oct 30 04:10:56 EDT 2020
On Fri, 30 Oct 2020 at 09:04, Nathan Chancellor
<natechancellor at gmail.com> wrote:
>
> On Fri, Oct 30, 2020 at 08:58:20AM +0100, Ard Biesheuvel wrote:
> > On Fri, 30 Oct 2020 at 08:57, Nathan Chancellor
> > <natechancellor at gmail.com> wrote:
> > >
> > > On Fri, Oct 30, 2020 at 08:52:53AM +0100, Ard Biesheuvel wrote:
> > > > On Fri, 30 Oct 2020 at 02:32, Nathan Chancellor
> > > > <natechancellor at gmail.com> wrote:
> > > > >
> > > > > On Thu, Oct 29, 2020 at 05:38:22PM -0700, Nick Desaulniers wrote:
> > > > > > On Thu, Oct 29, 2020 at 5:29 PM Nathan Chancellor
> > > > > > <natechancellor at gmail.com> wrote:
> > > > > > >
> > > > > > > On Mon, Oct 19, 2020 at 10:41:35AM +0200, Linus Walleij wrote:
> > > > > > > > This is the 16th and final (knock on wood) version of
> > > > > > > > KASan for ARM32.
> > > > > > > >
> > > > > > > > Changes since v15:
> > > > > > > >
> > > > > > > > - Things now work on all boards we have tested on including
> > > > > > > > Broadcom and i.MX6Q.
> > > > > > > >
> > > > > > > > - Folded in a fix from Ard to PAGE_ALIGN() the end of
> > > > > > > > mappings making everything work on all Broadcom board.
> > > > > > > >
> > > > > > > > - Folded in a fix from Ahmad Fatoum making things work
> > > > > > > > with fortify on i.MX6Q.
> > > > > > > >
> > > > > > > > - Testing and testing and testing on build servers.
> > > > > > > >
> > > > > > > > - We are good to go.
> > > > > > > >
> > > > > > > > I will now put this in Russell's patch tracker for v5.11.
> > > > > > > >
> > > > > > > > There is a git branch you can pull in:
> > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git/log/?h=kasan
> > > > > > > >
> > > > > > > > This branch includes Ard's two patches already in Russell's
> > > > > > > > patch tracker.
> > > > > > > >
> > > > > > > >
> > > > > > > > Abbott Liu (1):
> > > > > > > > ARM: Define the virtual space of KASan's shadow region
> > > > > > > >
> > > > > > > > Andrey Ryabinin (3):
> > > > > > > > ARM: Disable KASan instrumentation for some code
> > > > > > > > ARM: Replace string mem* functions for KASan
> > > > > > > > ARM: Enable KASan for ARM
> > > > > > > >
> > > > > > > > Linus Walleij (1):
> > > > > > > > ARM: Initialize the mapping of KASan shadow memory
> > > > > > > >
> > > > > > > > Documentation/arm/memory.rst | 5 +
> > > > > > > > Documentation/dev-tools/kasan.rst | 4 +-
> > > > > > > > .../features/debug/KASAN/arch-support.txt | 2 +-
> > > > > > > > arch/arm/Kconfig | 10 +
> > > > > > > > arch/arm/boot/compressed/Makefile | 1 +
> > > > > > > > arch/arm/boot/compressed/string.c | 19 ++
> > > > > > > > arch/arm/include/asm/kasan.h | 33 ++
> > > > > > > > arch/arm/include/asm/kasan_def.h | 81 +++++
> > > > > > > > arch/arm/include/asm/memory.h | 5 +
> > > > > > > > arch/arm/include/asm/pgalloc.h | 8 +-
> > > > > > > > arch/arm/include/asm/string.h | 26 ++
> > > > > > > > arch/arm/include/asm/thread_info.h | 8 +
> > > > > > > > arch/arm/include/asm/uaccess-asm.h | 2 +-
> > > > > > > > arch/arm/kernel/entry-armv.S | 3 +-
> > > > > > > > arch/arm/kernel/entry-common.S | 9 +-
> > > > > > > > arch/arm/kernel/head-common.S | 7 +-
> > > > > > > > arch/arm/kernel/setup.c | 2 +
> > > > > > > > arch/arm/kernel/unwind.c | 6 +-
> > > > > > > > arch/arm/lib/memcpy.S | 3 +
> > > > > > > > arch/arm/lib/memmove.S | 5 +-
> > > > > > > > arch/arm/lib/memset.S | 3 +
> > > > > > > > arch/arm/mm/Makefile | 5 +
> > > > > > > > arch/arm/mm/kasan_init.c | 292 ++++++++++++++++++
> > > > > > > > arch/arm/mm/mmu.c | 18 ++
> > > > > > > > arch/arm/mm/pgd.c | 16 +-
> > > > > > > > arch/arm/vdso/Makefile | 2 +
> > > > > > > > 26 files changed, 561 insertions(+), 14 deletions(-)
> > > > > > > > create mode 100644 arch/arm/include/asm/kasan.h
> > > > > > > > create mode 100644 arch/arm/include/asm/kasan_def.h
> > > > > > > > create mode 100644 arch/arm/mm/kasan_init.c
> > > > > > > >
> > > > > > > > --
> > > > > > > > 2.26.2
> > > > > > > >
> > > > > > >
> > > > > > > After this series was applied and available in -next, ARCH=arm LLVM=1
> > > > > > > allyesconfig builds started failing:
> > > > > > >
> > > > > > > $ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- KCONFIG_ALLCONFIG=<(echo CONFIG_CPU_BIG_ENDIAN=n) LLVM=1 distclean allyesconfig vmlinux
> > > > > > > ...
> > > > > > > ld.lld: error: section: .exit.data is not contiguous with other relro sections
> > > > > > > ...
> > > > > > >
> > > > > > > $ git bisect ld: [3f267ec60b922eff2a5c90d532357a39f155b730] Add linux-next specific files for 20201029
> > > > > > > # good: [23859ae44402f4d935b9ee548135dd1e65e2cbf4] Merge tag 'trace-v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
> > > > > > > git bisect start '3f267ec60b922eff2a5c90d532357a39f155b730' '23859ae44402f4d935b9ee548135dd1e65e2cbf4'
> > > > > > > # bad: [bfa70a4ea4bfa6f87b58cf8b90b88297389c92b7] Merge remote-tracking branch 'mtd/mtd/next' into master
> > > > > > > git bisect bad bfa70a4ea4bfa6f87b58cf8b90b88297389c92b7
> > > > > > > # bad: [37a292dcf77532547f335ed5063d9169031c9b08] Merge remote-tracking branch 'sunxi/sunxi/for-next' into master
> > > > > > > git bisect bad 37a292dcf77532547f335ed5063d9169031c9b08
> > > > > > > # good: [e6d922c77db276a16f0b7933c2a9951dc9c0052c] Merge remote-tracking branch 'drm-misc-fixes/for-linux-next-fixes' into master
> > > > > > > git bisect good e6d922c77db276a16f0b7933c2a9951dc9c0052c
> > > > > > > # bad: [cbe49fbb8f6c8d29bc1d9a5a9a742ef2c2eb6320] Merge remote-tracking branch 'mvebu/for-next' into master
> > > > > > > git bisect bad cbe49fbb8f6c8d29bc1d9a5a9a742ef2c2eb6320
> > > > > > > # bad: [d0e12484e7e1ede73c538744cdbe9439f7335d01] Merge remote-tracking branch 'arm-soc/for-next' into master
> > > > > > > git bisect bad d0e12484e7e1ede73c538744cdbe9439f7335d01
> > > > > > > # good: [24a23387c15f34bad2485a9e1c3b7ac6f0fb35a6] Merge branch 'asm-generic-cleanup' into asm-generic
> > > > > > > git bisect good 24a23387c15f34bad2485a9e1c3b7ac6f0fb35a6
> > > > > > > # good: [3a8eb4d3421a2ca0f95ac3b1a8f012940d4f0d52] Merge remote-tracking branch 'kbuild/for-next' into master
> > > > > > > git bisect good 3a8eb4d3421a2ca0f95ac3b1a8f012940d4f0d52
> > > > > > > # bad: [20f96e606509ee5084690179afe1810b95617a92] Merge branches 'fixes' and 'misc' into for-next
> > > > > > > git bisect bad 20f96e606509ee5084690179afe1810b95617a92
> > > > > > > # good: [d6d51a96c7d63b7450860a3037f2d62388286a52] ARM: 9014/2: Replace string mem* functions for KASan
> > > > > > > git bisect good d6d51a96c7d63b7450860a3037f2d62388286a52
> > > > > > > # good: [5615f69bc2097452ecc954f5264d784e158d6801] ARM: 9016/2: Initialize the mapping of KASan shadow memory
> > > > > > > git bisect good 5615f69bc2097452ecc954f5264d784e158d6801
> > > > > > > # bad: [fc2933c133744305236793025b00c2f7d258b687] ARM: 9020/1: mm: use correct section size macro to describe the FDT virtual address
> > > > > > > git bisect bad fc2933c133744305236793025b00c2f7d258b687
> > > > > > > # bad: [421015713b306e47af95d4d61cdfbd96d462e4cb] ARM: 9017/2: Enable KASan for ARM
> > > > > > > git bisect bad 421015713b306e47af95d4d61cdfbd96d462e4cb
> > > > > > > # first bad commit: [421015713b306e47af95d4d61cdfbd96d462e4cb] ARM: 9017/2: Enable KASan for ARMog
> > > > > > >
> > > > > > > An allyesconfig kernel compiled with clang does not link properly with
> > > > > > > ld.bfd without a workaround [1], which I do not have time to apply and
> > > > > > > test now but can later if it is relevant. I have not done any triage on
> > > > > > > this yet either but I wanted to get the report out in case there is
> > > > > > > anything obvious.
> > > > > > >
> > > > > > > [1]: https://github.com/ClangBuiltLinux/linux/issues/325
> > > > > >
> > > > > > relro? smells like:
> > > > > > https://lore.kernel.org/lkml/20201016175339.2429280-1-ndesaulniers@google.com/T/#u
> > > > > >
> > > > >
> > > > > Huh, did not even realize that the error messages were the same, my bad!
> > > > >
> > > > > This issue is simple enough to produce by just adding CONFIG_KASAN=y to
> > > > > multi_v7_defconfig. I tried adding '-z norelro' to LDFLAGS_vmlinux in
> > > > > arch/arm/Makefile and it fixes the build error but the resulting kernel
> > > > > does not boot in QEMU.
> > > > >
> > > > > $ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 distclean defconfig
> > > > >
> > > > > $ scripts/config -e KASAN
> > > > >
> > > > > $ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 olddefconfig zImage
> > > > >
> > > > > $ ~/cbl/github/boot-utils/boot-qemu.sh -a arm32_v7 -k .
> > > > > /home/nathan/cbl/github/boot-utils/images/arm/rootfs.cpio.zst: 3176448 bytes
> > > > > + timeout --foreground 3m unbuffer qemu-system-arm -machine virt -no-reboot -append 'console=ttyAMA0 ' -display none -initrd /home/nathan/cbl/github/boot-utils/images/arm/rootfs.cpio -kernel /home/nathan/src/linux-next/arch/arm/boot/zImage -m 512m -nodefaults -serial mon:stdio
> > > > > + RET=124
> > > > > + set +x
> > > > >
> > > > > '-z norelro' boots fine without KASAN so I assume there is something up
> > > > > specifically with KASAN and LLVM for ARM.
> > > > >
> > > >
> > > > How long did you wait for it to boot? Booting a KASAN kernel under
> > > > QEMU emulation is going to be *very* slow.
> > >
> > > The timeout command above is 3m and there was no output from the kernel
> > > in that amount of time. What kind of time should I be reasonably
> > > expecting?
> > >
> >
> > 3 minutes is probably long enough.
> >
> > Do you see any output with 'earlycon=pl011,0x9000000' added to the
> > kernel command line?
>
> Yes.
>
> $ ~/cbl/github/boot-utils/boot-qemu.sh -a arm32_v7 -k .
> /home/nathan/cbl/github/boot-utils/images/arm/rootfs.cpio.zst: 3176448 bytes
> + timeout --foreground 3m unbuffer qemu-system-arm -machine virt -no-reboot -append 'console=ttyAMA0 earlycon=pl011,0x9000000 ' -display none -initrd /home/nathan/cbl/github/boot-utils/images/arm/rootfs.cpio -kernel /home/nathan/src/linux-next/arch/arm/boot/zImage -m 512m -nodefaults -serial mon:stdio
> [ 0.000000] Booting Linux on physical CPU 0x0
> [ 0.000000] Linux version 5.10.0-rc1-next-20201029-dirty (nathan at ubuntu-m3-large-x86) (ClangBuiltLinux clang version 12.0.0 (https://github.com/llvm/llvm-project 1df8d7b4f23da304061bf30b617132f8ba9ab80a), LLD 12.0.0 (https://github.com/llvm/llvm-project 1df8d7b4f23da304061bf30b617132f8ba9ab80a)) #1 SMP Thu Oct 29 18:26:00 MST 2020
> [ 0.000000] CPU: ARMv7 Processor [412fc0f1] revision 1 (ARMv7), cr=10c5387d
> [ 0.000000] CPU: div instructions available: patching division code
> [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
> [ 0.000000] OF: fdt: Machine model: linux,dummy-virt
> [ 0.000000] earlycon: pl11 at MMIO 0x09000000 (options '')
> [ 0.000000] printk: bootconsole [pl11] enabled
> [ 0.000000] Memory policy: Data cache writealloc
> [ 0.000000] efi: UEFI not found.
> [ 0.000000] cma: Reserved 64 MiB at 0x5c000000
> [ 0.000000] Zone ranges:
> [ 0.000000] DMA [mem 0x0000000040000000-0x000000005fffffff]
> [ 0.000000] Normal empty
> [ 0.000000] HighMem empty
> [ 0.000000] Movable zone start for each node
> [ 0.000000] Early memory node ranges
> [ 0.000000] node 0: [mem 0x0000000040000000-0x000000005fffffff]
> [ 0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x000000005fffffff]
> [ 0.000000] kasan: Mapping kernel virtual memory block: c0000000-e0000000 at shadow: b7000000-bb000000
> [ 0.000000] kasan: Mapping kernel virtual memory block: bf000000-c0000000 at shadow: b6e00000-b7000000
> [ 0.000000] kasan: Kernel address sanitizer initialized
> [ 0.000000] psci: probing for conduit method from DT.
> [ 0.000000] psci: PSCIv0.2 detected in firmware.
> [ 0.000000] psci: Using standard PSCI v0.2 function IDs
> [ 0.000000] psci: Trusted OS migration not required
> [ 0.000000] percpu: Embedded 20 pages/cpu s49676 r8192 d24052 u81920
> [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 130048
> [ 0.000000] Kernel command line: console=ttyAMA0 earlycon=pl011,0x9000000
> [ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
> [ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes, linear)
> [ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
> [ 0.000000] Memory: 329852K/524288K available (21504K kernel code, 8544K rwdata, 14676K rodata, 2048K init, 4843K bss, 128900K reserved, 65536K cma-reserved, 0K highmem)
> [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
> [ 0.000000] rcu: Hierarchical RCU implementation.
> [ 0.000000] rcu: RCU event tracing is enabled.
> [ 0.000000] rcu: RCU restricting CPUs from NR_CPUS=16 to nr_cpu_ids=1.
> [ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
> [ 0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
> [ 0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
> [ 0.000000] GICv2m: range[mem 0x08020000-0x08020fff], SPI[80:143]
> [ 0.000000] random: get_random_bytes called from start_kernel+0x208/0x3d0 with crng_init=0
> [ 0.000000] arch_timer: cp15 timer(s) running at 62.50MHz (virt).
> [ 0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x1cd42e208c, max_idle_ns: 881590405314 ns
> [ 0.000156] sched_clock: 56 bits at 62MHz, resolution 16ns, wraps every 4398046511096ns
> [ 0.000565] Switching to timer-based delay loop, resolution 16ns
> [ 0.006124] Console: colour dummy device 80x30
> [ 0.007840] Calibrating delay loop (skipped), value calculated using timer frequency.. 125.00 BogoMIPS (lpj=625000)
> [ 0.011577] pid_max: default: 32768 minimum: 301
> [ 0.014889] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
> [ 0.015189] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
> [ 0.043926] CPU: Testing write buffer coherency: ok
> [ 0.045820] CPU0: Spectre v2: firmware did not set auxiliary control register IBE bit, system vulnerable
> [ 0.057716] /cpus/cpu at 0 missing clock-frequency property
> [ 0.058105] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
> [ 0.070417] Setting up static identity map for 0x40300000 - 0x403000ac
> [ 0.075105] rcu: Hierarchical SRCU implementation.
> [ 0.084843] EFI services will not be available.
> [ 0.087124] smp: Bringing up secondary CPUs ...
> [ 0.087384] smp: Brought up 1 node, 1 CPU
> [ 0.087617] SMP: Total of 1 processors activated (125.00 BogoMIPS).
> [ 0.087878] CPU: All CPU(s) started in SVC mode.
> [ 0.105778] devtmpfs: initialized
> [ 0.283349] VFP support v0.3: implementor 41 architecture 4 part 30 variant f rev 0
> [ 0.310896] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
> [ 0.311679] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.312469] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.312803] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.313125] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.313445] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.313761] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.314082] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.314400] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.314718] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.315031] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
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> [ 0.326255] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
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> [ 0.328138] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
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> [ 0.329081] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.329400] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.329711] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.330021] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.330326] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
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> [ 0.331104] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.331417] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.331733] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.332054] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.332381] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.332696] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.333001] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.333320] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.333648] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.333964] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.334272] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.334580] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.334894] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.335212] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.335528] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.335846] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.336162] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.336482] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.336804] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.337124] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.337443] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.337761] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.338087] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.338414] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.338756] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.339074] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.339396] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.339737] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.340061] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.340379] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.340695] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.341161] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.341504] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.341843] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.342151] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.342492] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.342809] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.343129] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.343445] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.343761] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.344079] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.344410] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.344755] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.345066] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.345383] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.345719] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.346031] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.346350] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.346664] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.346976] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.347289] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.347642] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.347952] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.348275] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.348618] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.348930] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.349245] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.349563] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.349872] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.350191] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.350508] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.350832] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.351280] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.351632] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.351940] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.352257] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.352604] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.352918] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.353228] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.353543] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.353855] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.354170] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.354503] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.354833] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.355144] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.355477] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.355811] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.356133] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.356439] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.356757] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.357075] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.357381] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.357726] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.358037] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.358345] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.358663] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.358979] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.359287] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.359599] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.359911] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.360230] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.360549] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.360860] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.361313] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.361642] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.361953] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.362262] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.362578] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.362888] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.363205] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.363520] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.363821] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.364139] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.364445] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.364759] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.365070] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.365384] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.365695] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.366003] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.366306] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.366611] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.366924] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.367248] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.367569] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.367876] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.368197] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.368515] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.368829] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.369137] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.369454] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.369772] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.370079] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.370393] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.370709] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.371023] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.371490] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.371808] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.372122] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.372435] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
> [ 0.372767] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
>
> Then there is no output after that.
>
Ouch. This looks like futex_init() is being called over and over
again, which is a core_initcall.
This will need some dissecting of the binary, but we need to figure
out what is going on in the initcall dispatch code.
If you build with symbols, you should be able to run it in the
debugger. Just set a breakpoint on futex_init() and step through the
code until you can observe how/why it is being called a second time.
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