On Mon, 16 May 2022 14:58:28 +0100, Naresh Kamboju naresh.kamboju@linaro.org wrote:
Hi Marc,
Thanks for looking into this report.
On Mon, 16 May 2022 at 12:38, Marc Zyngier maz@kernel.org wrote:
On Mon, 16 May 2022 07:16:22 +0100, Naresh Kamboju naresh.kamboju@linaro.org wrote:
The kernel crash reported on arm64 juno-r2 device with kselftest-merge config while booting Linux next-20220513 kernel [1].
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Huh. Who inserts random BRKs like this?
[ 0.000000] Internal error: BRK handler: f20003e8 [#1] PREEMPT SMP [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.18.0-rc6-next-20220513 #1 [ 0.000000] Hardware name: ARM Juno development board (r2) (DT) [ 0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 0.000000] pc : gic_dist_config+0x4c/0x68 [ 0.000000] lr : gic_init_bases+0xd4/0x248
Please provide a disassembly of this function.
objdump snipper is here. http://ix.io/3XUW
Wrong function (I wasn't clear I wanted the breaking function, not the caller).
The vmlinux file is located in this url Please make use of it. http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/juno/lkft/linux-next...
ffff8000087f9908 <gic_dist_config>: ffff8000087f9908: a9bd7bfd stp x29, x30, [sp, #-48]! ffff8000087f990c: 910003fd mov x29, sp ffff8000087f9910: a90153f3 stp x19, x20, [sp, #16] ffff8000087f9914: f90013f5 str x21, [sp, #32] ffff8000087f9918: 2a0103f3 mov w19, w1 ffff8000087f991c: aa0003f4 mov x20, x0 ffff8000087f9920: aa0203f5 mov x21, x2 ffff8000087f9924: aa1e03e0 mov x0, x30 ffff8000087f9928: 97e0de72 bl ffff8000080312f0 <_mcount> ffff8000087f992c: 7100827f cmp w19, #0x20 ffff8000087f9930: 54000149 b.ls ffff8000087f9958 <gic_dist_config+0x50> // b.plast ffff8000087f9934: 52800402 mov w2, #0x20 // #32 ffff8000087f9938: 53027c40 lsr w0, w2, #2 ffff8000087f993c: 91300000 add x0, x0, #0xc00 ffff8000087f9940: 8b000280 add x0, x20, x0 ffff8000087f9944: b900001f str wzr, [x0] ffff8000087f9948: 11004042 add w2, w2, #0x10 ffff8000087f994c: 6b02027f cmp w19, w2 ffff8000087f9950: 54ffff48 b.hi ffff8000087f9938 <gic_dist_config+0x30> // b.pmore ffff8000087f9954: d4207d00 brk #0x3e8
What the hell is this??? This function has no WARN_ON, no BUG_ON, the allowed values for the immediate are:
#define KPROBES_BRK_IMM 0x004 #define UPROBES_BRK_IMM 0x005 #define KPROBES_BRK_SS_IMM 0x006 #define FAULT_BRK_IMM 0x100 #define KGDB_DYN_DBG_BRK_IMM 0x400 #define KGDB_COMPILED_DBG_BRK_IMM 0x401 #define BUG_BRK_IMM 0x800 #define KASAN_BRK_IMM 0x900 #define KASAN_BRK_MASK 0x0ff
and 0x3e8 isn't one of them. This seems like a GCC 'division by zero' hack, but there are no divisions by zero here. Your kernel is also full of the stuff.
What sort of odd options do you have? I can't help but notice that you have the Rust stuff in your tree. Can you please start by disabling this, just in case there is an interaction with your toolchain?
Thanks,
M.