Hello, kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on: commit: 50618d443add4eda4aa94c76fb56e72783c260ae ("[PATCH 3/4] Revert "of: reserved_mem: Use unflatten_devicetree APIs to scan reserved memory nodes"") url: https://github.com/intel-lab-lkp/linux/commits/Oreoluwa-Babatunde/Revert-of-reserved_mem-Restructure-code-to-call-reserved-mem-init-functions-earlier/20240709-073454 base: https://git.kernel.org/cgit/linux/kernel/git/robh/linux.git for-next patch subject: [PATCH 3/4] Revert "of: reserved_mem: Use unflatten_devicetree APIs to scan reserved memory nodes" in testcase: boot compiler: clang-18 test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G (please refer to attached dmesg/kmsg for entire log/backtrace) +---------------------------------------------+------------+------------+ | | 20cf0f8c96 | 50618d443a | +---------------------------------------------+------------+------------+ | boot_successes | 18 | 0 | | boot_failures | 0 | 18 | | BUG:kernel_NULL_pointer_dereference,address | 0 | 18 | | Oops | 0 | 18 | | RIP:fdt_ro_probe | 0 | 18 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 18 | +---------------------------------------------+------------+------------+ If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-lkp/202407161521.ec4d9668-lkp@xxxxxxxxx [ 0.082892][ T0] BUG: kernel NULL pointer dereference, address: 0000000000000004 [ 0.085157][ T0] #PF: supervisor read access in kernel mode [ 0.086877][ T0] #PF: error_code(0x0000) - not-present page [ 0.088532][ T0] PGD 0 P4D 0 [ 0.089466][ T0] Oops: Oops: 0000 [#1] PREEMPT [ 0.090747][ T0] CPU: 0 PID: 0 Comm: swapper Tainted: G T 6.10.0-rc1-00046-g50618d443add #1 [ 0.093729][ T0] RIP: 0010:fdt_ro_probe_ (scripts/dtc/libfdt/libfdt.h:? lib/../scripts/dtc/libfdt/fdt.c:?) [ 0.095168][ T0] Code: cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 b8 24 59 c7 5e b8 ed ff ff ff 40 f6 c7 07 74 07 31 c9 31 ff 31 d2 c3 <8b> 4f 04 8b 17 0f ca 81 fa 12 01 f2 2f 74 28 b8 f7 ff ff ff 81 fa All code ======== 0: cc int3 1: cc int3 2: cc int3 3: cc int3 4: cc int3 5: cc int3 6: cc int3 7: cc int3 8: 90 nop 9: 90 nop a: 90 nop b: 90 nop c: 90 nop d: 90 nop e: 90 nop f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: b8 24 59 c7 5e mov $0x5ec75924,%eax 18: b8 ed ff ff ff mov $0xffffffed,%eax 1d: 40 f6 c7 07 test $0x7,%dil 21: 74 07 je 0x2a 23: 31 c9 xor %ecx,%ecx 25: 31 ff xor %edi,%edi 27: 31 d2 xor %edx,%edx 29: c3 ret 2a:* 8b 4f 04 mov 0x4(%rdi),%ecx <-- trapping instruction 2d: 8b 17 mov (%rdi),%edx 2f: 0f ca bswap %edx 31: 81 fa 12 01 f2 2f cmp $0x2ff20112,%edx 37: 74 28 je 0x61 39: b8 f7 ff ff ff mov $0xfffffff7,%eax 3e: 81 .byte 0x81 3f: fa cli Code starting with the faulting instruction =========================================== 0: 8b 4f 04 mov 0x4(%rdi),%ecx 3: 8b 17 mov (%rdi),%edx 5: 0f ca bswap %edx 7: 81 fa 12 01 f2 2f cmp $0x2ff20112,%edx d: 74 28 je 0x37 f: b8 f7 ff ff ff mov $0xfffffff7,%eax 14: 81 .byte 0x81 15: fa cli [ 0.100859][ T0] RSP: 0000:ffffffff83e03e28 EFLAGS: 00010046 [ 0.102634][ T0] RAX: 00000000ffffffed RBX: 0000000000000000 RCX: 0000000000000000 [ 0.104925][ T0] RDX: 0000000000000010 RSI: ffffffff83ae68e5 RDI: 0000000000000000 [ 0.107172][ T0] RBP: 0000000000000010 R08: 0000000000000000 R09: 0000000000000000 [ 0.109427][ T0] R10: ffff88843fff2200 R11: 0000000000000000 R12: 0000000000000000 [ 0.111656][ T0] R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff83ae68e5 [ 0.113969][ T0] FS: 0000000000000000(0000) GS:ffffffff83eb3000(0000) knlGS:0000000000000000 [ 0.116389][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.118314][ T0] CR2: 0000000000000004 CR3: 0000000003ea3000 CR4: 00000000000000b0 [ 0.120569][ T0] Call Trace: [ 0.121512][ T0] <TASK> [ 0.122317][ T0] ? __die_body (arch/x86/kernel/dumpstack.c:421) [ 0.123615][ T0] ? page_fault_oops (arch/x86/mm/fault.c:711) [ 0.125110][ T0] ? console_flush_all (include/linux/rcupdate.h:? include/linux/srcu.h:232 kernel/printk/printk.c:286 kernel/printk/printk.c:2986) [ 0.126609][ T0] ? exc_page_fault (arch/x86/include/asm/paravirt.h:687) [ 0.127940][ T0] ? asm_exc_page_fault (arch/x86/include/asm/idtentry.h:623) [ 0.129365][ T0] ? fdt_ro_probe_ (scripts/dtc/libfdt/libfdt.h:? lib/../scripts/dtc/libfdt/fdt.c:?) [ 0.130637][ T0] ? fdt_path_offset_namelen (lib/../scripts/dtc/libfdt/fdt_ro.c:256) [ 0.132233][ T0] ? fdt_scan_reserved_mem_reg_nodes (drivers/of/of_reserved_mem.c:?) [ 0.134085][ T0] ? fdt_init_reserved_mem (drivers/of/of_reserved_mem.c:550) [ 0.135650][ T0] ? x86_flattree_get_config (arch/x86/kernel/devicetree.c:313) [ 0.137230][ T0] ? setup_arch (arch/x86/kernel/setup.c:1099) [ 0.138552][ T0] ? start_kernel (init/main.c:481 init/main.c:927) [ 0.139865][ T0] ? x86_64_start_reservations (??:?) [ 0.141519][ T0] ? x86_64_start_kernel (??:?) [ 0.142935][ T0] ? common_startup_64 (arch/x86/kernel/head_64.S:421) [ 0.144349][ T0] </TASK> [ 0.145232][ T0] Modules linked in: [ 0.146391][ T0] CR2: 0000000000000004 [ 0.147628][ T0] ---[ end trace 0000000000000000 ]--- [ 0.149306][ T0] RIP: 0010:fdt_ro_probe_ (scripts/dtc/libfdt/libfdt.h:? lib/../scripts/dtc/libfdt/fdt.c:?) [ 0.150885][ T0] Code: cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 b8 24 59 c7 5e b8 ed ff ff ff 40 f6 c7 07 74 07 31 c9 31 ff 31 d2 c3 <8b> 4f 04 8b 17 0f ca 81 fa 12 01 f2 2f 74 28 b8 f7 ff ff ff 81 fa All code ======== 0: cc int3 1: cc int3 2: cc int3 3: cc int3 4: cc int3 5: cc int3 6: cc int3 7: cc int3 8: 90 nop 9: 90 nop a: 90 nop b: 90 nop c: 90 nop d: 90 nop e: 90 nop f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: b8 24 59 c7 5e mov $0x5ec75924,%eax 18: b8 ed ff ff ff mov $0xffffffed,%eax 1d: 40 f6 c7 07 test $0x7,%dil 21: 74 07 je 0x2a 23: 31 c9 xor %ecx,%ecx 25: 31 ff xor %edi,%edi 27: 31 d2 xor %edx,%edx 29: c3 ret 2a:* 8b 4f 04 mov 0x4(%rdi),%ecx <-- trapping instruction 2d: 8b 17 mov (%rdi),%edx 2f: 0f ca bswap %edx 31: 81 fa 12 01 f2 2f cmp $0x2ff20112,%edx 37: 74 28 je 0x61 39: b8 f7 ff ff ff mov $0xfffffff7,%eax 3e: 81 .byte 0x81 3f: fa cli Code starting with the faulting instruction =========================================== 0: 8b 4f 04 mov 0x4(%rdi),%ecx 3: 8b 17 mov (%rdi),%edx 5: 0f ca bswap %edx 7: 81 fa 12 01 f2 2f cmp $0x2ff20112,%edx d: 74 28 je 0x37 f: b8 f7 ff ff ff mov $0xfffffff7,%eax 14: 81 .byte 0x81 15: fa cli The kernel config and materials to reproduce are available at: https://download.01.org/0day-ci/archive/20240716/202407161521.ec4d9668-lkp@xxxxxxxxx -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki