On Wed, 10 Feb 2016, Geert Uytterhoeven wrote: > If CONFIG_DEBUG_RODATA=y, the kernel crashes during system suspend: > > Freezing user space processes ... (elapsed 0.004 seconds) done. > Freezing remaining freezable tasks ... (elapsed 0.002 seconds) > done. > PM: suspend of devices complete after 111.948 msecs > PM: late suspend of devices complete after 1.086 msecs > PM: noirq suspend of devices complete after 11.576 msecs > Disabling non-boot CPUs ... > Kernel panic - not syncing: Attempted to kill the idle task! > 1014ec ---[ end Kernel panic - not syncing: Attempted to kill the idle > task! > CPU0: stopping > > This happens because the .text section is marked read-only, while the > arrays shmobile_smp_mpidr[], shmobile_smp_fn[], and shmobile_smp_arg[] > are being written to. > > Fix this by moving these arrays from the .text to the .data section. > This requires accessing them through PC-relative offsets. > > Signed-off-by: Geert Uytterhoeven <[email protected]> > Reviewed-by: Kees Cook <[email protected]>
You could replace .data with .bss to avoid allocating zero-initialized space in the kernel binary. Then you may add Reviewed-by: Nicolas Pitre <[email protected]> > --- > v2: > - Add Reviewed-by, > - Store offsets instead of pointers, as suggested by Nicolas Pitre > <[email protected]>. > --- > arch/arm/mach-shmobile/headsmp.S | 20 ++++++++++++++------ > 1 file changed, 14 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/mach-shmobile/headsmp.S > b/arch/arm/mach-shmobile/headsmp.S > index 330c1fc63197df89..4cf7f0b016b0b0fe 100644 > --- a/arch/arm/mach-shmobile/headsmp.S > +++ b/arch/arm/mach-shmobile/headsmp.S > @@ -50,9 +50,11 @@ ENTRY(shmobile_smp_boot) > mrc p15, 0, r1, c0, c0, 5 @ r1 = MPIDR > and r0, r1, r0 @ r0 = cpu_logical_map() value > mov r1, #0 @ r1 = CPU index > - adr r5, 1f @ array of per-cpu mpidr values > - adr r6, 2f @ array of per-cpu functions > - adr r7, 3f @ array of per-cpu arguments > + adr r2, 1f > + ldmia r2, {r5, r6, r7} > + add r5, r5, r2 @ array of per-cpu mpidr values > + add r6, r6, r2 @ array of per-cpu functions > + add r7, r7, r2 @ array of per-cpu arguments > > shmobile_smp_boot_find_mpidr: > ldr r8, [r5, r1, lsl #2] > @@ -80,12 +82,18 @@ ENTRY(shmobile_smp_sleep) > b shmobile_smp_boot > ENDPROC(shmobile_smp_sleep) > > + .align 2 > +1: .long shmobile_smp_mpidr - . > + .long shmobile_smp_fn - 1b > + .long shmobile_smp_arg - 1b > + > + .data > .globl shmobile_smp_mpidr > shmobile_smp_mpidr: > -1: .space NR_CPUS * 4 > + .space NR_CPUS * 4 > .globl shmobile_smp_fn > shmobile_smp_fn: > -2: .space NR_CPUS * 4 > + .space NR_CPUS * 4 > .globl shmobile_smp_arg > shmobile_smp_arg: > -3: .space NR_CPUS * 4 > + .space NR_CPUS * 4 > -- > 1.9.1 > >
