On Sun, Jan 29, 2017 at 03:42:55PM +0530, Yury Norov wrote:

Hi all,

I pulled next-20170125 kernel, and found it hanged on boot. The exact reason is
panic on dereferencing of the 0xffffffc8 address, which is most probably the
attempt to dereference the ENOSYS error code as the address. next-20170124 works
fine, at least it boots.

Does anyone have details on that?

Yury

UPD:

I run qemu for testing.

The true failure backtrace is like below. The bad dereference happens for me in
arm_smccc_hvc() function in macro SMCCC.

Yury

Backtrace:

#0  0xffff00000808f7a8 in arm_smccc_hvc () at
arch/arm64/kernel/smccc-call.S:50
#1  0xffff000008745ea0 in __invoke_psci_fn_hvc (function_id=<optimized out>, arg0=<optimized out>,
    arg1=<optimized out>, arg2=<optimized out>) at drivers/firmware/psci.c:119
#2  0xffff000008745d18 in psci_migrate_info_type () at drivers/firmware/psci.c:204
#3  0xffff000008ca150c in psci_init_migrate () at drivers/firmware/psci.c:465
#4  psci_probe () at drivers/firmware/psci.c:539
#5  0xffff000008ca1684 in psci_0_2_init (np=<optimized out>) at drivers/firmware/psci.c:571
#6  0xffff000008ca16d8 in psci_dt_init () at drivers/firmware/psci.c:637
#7  0xffff000008c62914 in setup_arch (cmdline_p=<optimized out>) at arch/arm64/kernel/setup.c:287
#8  0xffff000008c6082c in start_kernel () at init/main.c:509
#9  0xffff000008c601e0 in __primary_switched () at arch/arm64/kernel/head.S:452

Listing:

 ?0xffff00000808f790 <arm_smccc_hvc>        hvc    #0x0
 ?0xffff00000808f794 <arm_smccc_hvc+4>      ldr    x4, [sp]
 ?0xffff00000808f798 <arm_smccc_hvc+8>      stp    x0, x1, [x4]          
 ?0xffff00000808f79c <arm_smccc_hvc+12>     stp x2, x3, [x4,#16]
 ?0xffff00000808f7a0 <arm_smccc_hvc+16>     ldr x4, [sp,#8] 
 ?0xffff00000808f7a4 <arm_smccc_hvc+20>     cbz x4, 0xffff00000808f7b8 <arm_smccc_hvc+40>

?0xffff00000808f7a8 <arm_smccc_hvc+24      ldr    x9, [x4]

 ?0xffff00000808f7ac <arm_smccc_hvc+28>     cmp    x9, #0x1
 ?0xffff00000808f7b0 <arm_smccc_hvc+32>     b.ne   0xffff00000808f7b8 <arm_smccc_hvc+40>
 ?0xffff00000808f7b4 <arm_smccc_hvc+36>     str    x6, [x4,#8]
 ?0xffff00000808f7b8 <arm_smccc_hvc+40>     ret