linux/arch/riscv
Alexandre Ghiti 76950340cf
riscv: Use READ_ONCE_NOCHECK in imprecise unwinding stack mode
When CONFIG_FRAME_POINTER is unset, the stack unwinding function
walk_stackframe randomly reads the stack and then, when KASAN is enabled,
it can lead to the following backtrace:

[    0.000000] ==================================================================
[    0.000000] BUG: KASAN: stack-out-of-bounds in walk_stackframe+0xa6/0x11a
[    0.000000] Read of size 8 at addr ffffffff81807c40 by task swapper/0
[    0.000000]
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.2.0-12919-g24203e6db61f #43
[    0.000000] Hardware name: riscv-virtio,qemu (DT)
[    0.000000] Call Trace:
[    0.000000] [<ffffffff80007ba8>] walk_stackframe+0x0/0x11a
[    0.000000] [<ffffffff80099ecc>] init_param_lock+0x26/0x2a
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff80c49c80>] dump_stack_lvl+0x22/0x36
[    0.000000] [<ffffffff80c3783e>] print_report+0x198/0x4a8
[    0.000000] [<ffffffff80099ecc>] init_param_lock+0x26/0x2a
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff8015f68a>] kasan_report+0x9a/0xc8
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff80007c4a>] walk_stackframe+0xa2/0x11a
[    0.000000] [<ffffffff8006e99c>] desc_make_final+0x80/0x84
[    0.000000] [<ffffffff8009a04e>] stack_trace_save+0x88/0xa6
[    0.000000] [<ffffffff80099fc2>] filter_irq_stacks+0x72/0x76
[    0.000000] [<ffffffff8006b95e>] devkmsg_read+0x32a/0x32e
[    0.000000] [<ffffffff8015ec16>] kasan_save_stack+0x28/0x52
[    0.000000] [<ffffffff8006e998>] desc_make_final+0x7c/0x84
[    0.000000] [<ffffffff8009a04a>] stack_trace_save+0x84/0xa6
[    0.000000] [<ffffffff8015ec52>] kasan_set_track+0x12/0x20
[    0.000000] [<ffffffff8015f22e>] __kasan_slab_alloc+0x58/0x5e
[    0.000000] [<ffffffff8015e7ea>] __kmem_cache_create+0x21e/0x39a
[    0.000000] [<ffffffff80e133ac>] create_boot_cache+0x70/0x9c
[    0.000000] [<ffffffff80e17ab2>] kmem_cache_init+0x6c/0x11e
[    0.000000] [<ffffffff80e00fd6>] mm_init+0xd8/0xfe
[    0.000000] [<ffffffff80e011d8>] start_kernel+0x190/0x3ca
[    0.000000]
[    0.000000] The buggy address belongs to stack of task swapper/0
[    0.000000]  and is located at offset 0 in frame:
[    0.000000]  stack_trace_save+0x0/0xa6
[    0.000000]
[    0.000000] This frame has 1 object:
[    0.000000]  [32, 56) 'c'
[    0.000000]
[    0.000000] The buggy address belongs to the physical page:
[    0.000000] page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x81a07
[    0.000000] flags: 0x1000(reserved|zone=0)
[    0.000000] raw: 0000000000001000 ff600003f1e3d150 ff600003f1e3d150 0000000000000000
[    0.000000] raw: 0000000000000000 0000000000000000 00000001ffffffff
[    0.000000] page dumped because: kasan: bad access detected
[    0.000000]
[    0.000000] Memory state around the buggy address:
[    0.000000]  ffffffff81807b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000]  ffffffff81807b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000] >ffffffff81807c00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 f3
[    0.000000]                                            ^
[    0.000000]  ffffffff81807c80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000]  ffffffff81807d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[    0.000000] ==================================================================

Fix that by using READ_ONCE_NOCHECK when reading the stack in imprecise
mode.

Fixes: 5d8544e2d0 ("RISC-V: Generic library routines and assembly")
Reported-by: Chathura Rajapaksha <chathura.abeyrathne.lk@gmail.com>
Link: https://lore.kernel.org/all/CAD7mqryDQCYyJ1gAmtMm8SASMWAQ4i103ptTb0f6Oda=tPY2=A@mail.gmail.com/
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230308091639.602024-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-09 14:50:35 -08:00
..
boot SoC: DT changes for 6.3 2023-02-20 15:49:56 -08:00
configs riscv: defconfig: Enable the Allwinner D1 platform and drivers 2023-01-27 23:10:08 +01:00
errata RISC-V: fix taking the text_mutex twice during sifive errata patching 2023-03-07 12:39:12 -08:00
include RISC-V Patches for the 6.3 Merge Window, Part 2 2023-03-03 09:32:51 -08:00
kernel riscv: Use READ_ONCE_NOCHECK in imprecise unwinding stack mode 2023-03-09 14:50:35 -08:00
kvm ARM: 2023-02-25 11:30:21 -08:00
lib riscv, lib: Fix Zbb strncmp 2023-02-28 18:42:38 -08:00
mm VM_FAULT_RETRY fixes 2023-03-05 11:07:58 -08:00
net riscv, bpf: Add bpf trampoline support for RV64 2023-02-17 21:45:30 +01:00
purgatory RISC-V: add infrastructure to allow different str* implementations 2023-01-31 11:43:23 -08:00
Kbuild riscv: move errata/ and kvm/ builds to arch/riscv/Kbuild 2022-06-01 22:26:32 -07:00
Kconfig RISC-V Patches for the 6.3 Merge Window, Part 1 2023-02-25 11:14:08 -08:00
Kconfig.debug
Kconfig.erratas drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores 2022-10-27 14:35:20 -07:00
Kconfig.socs RISC-V Patches for the 6.3 Merge Window, Part 1 2023-02-25 11:14:08 -08:00
Makefile RISC-V: Stop emitting attributes 2023-03-06 15:55:25 -08:00