Hello When using an initrd > 5M, I hit the following kernel crash: qemu-system-sparc -kernel vmlinux -initrd rootfs.cpio.gz -nographic Configuration device id QEMU version 1 machine id 32 Probing SBus slot 0 offset 0 Probing SBus slot 1 offset 0 Probing SBus slot 2 offset 0 Probing SBus slot 3 offset 0 Probing SBus slot 4 offset 0 Probing SBus slot 5 offset 0 Invalid FCode start byte CPUs: 1 x FMI,MB86904 UUID: 00000000-0000-0000-0000-000000000000 Welcome to OpenBIOS v1.1 built on Oct 5 2018 08:20 Type 'help' for detailed information [sparc] Kernel already loaded switching to new context: PROMLIB: obio_ranges 1 [ 0.000000] PROMLIB: Sun Boot Prom Version 3 Revision 2 [ 0.000000] Linux version 4.20.0-next-20190102+ (compile@Red) (gcc version 7.3.0 (Gentoo 7.3.0-r3 p1.4)) #148 Thu Jan 3 16:17:08 CET 2019 [ 0.000000] printk: bootconsole [earlyprom0] enabled [ 0.000000] ARCH: SUN4M [ 0.000000] TYPE: SPARCstation 5 [ 0.000000] Ethernet address: 52:54:00:12:34:56 [ 0.000000] Unable to handle kernel NULL pointer dereference [ 0.000000] tsk->{mm,active_mm}->context = ffffffff [ 0.000000] tsk->{mm,active_mm}->pgd = 00000000 [ 0.000000] \|/ ____ \|/ [ 0.000000] "@'/ ,. \`@" [ 0.000000] /_| \__/ |_\ [ 0.000000] \__U_/ [ 0.000000] swapper(0): Oops [#1] [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.20.0-next-20190102+ #148 [ 0.000000] PSR: 04001fc0 PC: f0010ef0 NPC: f0010ef4 Y: 00000000 Not tainted [ 0.000000] PC: <do_sparc_fault+0x158/0x404> [ 0.000000] %G: 0000000a 000003c4 f05ece08 f05ecc00 00000000 00e00000 f05d4000 00000001 [ 0.000000] %O: 00000000 00e00000 00800000 00e00000 00000000 00000002 f05d5bb8 f00bba58 [ 0.000000] RPC: <memblock_reserve+0x38/0x68> [ 0.000000] %L: 00000040 f05dfaf8 f05d5c68 00000001 0003ffff 006951e0 f05ed014 f0674ab4 [ 0.000000] %I: f05d5c80 00000000 00000002 f1000000 ffffffff 00000000 f05d5c20 f0007fd8 [ 0.000000] Disabling lock debugging due to kernel taint [ 0.000000] Caller[f0007fd8]: srmmu_fault+0x58/0x68 [ 0.000000] Caller[f0618598]: memblock_alloc_try_nid+0xb8/0xc8 [ 0.000000] Caller[f0611094]: srmmu_paging_init+0x174/0xaf8 [ 0.000000] Caller[f06106a8]: paging_init+0x4/0x24 [ 0.000000] Caller[f060e4f0]: setup_arch+0x3e8/0x480 [ 0.000000] Caller[f060ab50]: start_kernel+0x48/0x460 [ 0.000000] Caller[f060a43c]: continue_boot+0x324/0x334 [ 0.000000] Caller[00000000]: (null) [ 0.000000] Instruction DUMP: [ 0.000000] c800a024 [ 0.000000] 83286002 [ 0.000000] 073c17b3 [ 0.000000] <c4010001> [ 0.000000] c600e22c [ 0.000000] 8a08a003 [ 0.000000] 80a16001 [ 0.000000] 0280003b [ 0.000000] c600c001 [ 0.000000] [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! [ 0.000000] Press Stop-A (L1-A) from sun keyboard or send break [ 0.000000] twice on console to return to the boot prom [ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- qemu-system-sparc: terminating on signal 15 from pid 13043 (killall)
The NULL ptr dereference is done by memset() in srmmu_nocache_init() and memblock_alloc_try_nid(). If I comment both memset, the boot pass But since nothing explain the NULL ptr deref in memset(), I suspect something is overriden by the initrd Regards