diff options
| author | Nam Cao <[email protected]> | 2024-11-19 12:10:56 +0100 |
|---|---|---|
| committer | Palmer Dabbelt <[email protected]> | 2025-01-08 10:39:39 -0800 |
| commit | 13134cc949148e1dfa540a0fe5dc73569bc62155 (patch) | |
| tree | fe3ebd2c2ac507a9fa9f103e1d6b4445455bf958 | |
| parent | 6a97f4118ac07cfdc316433f385dbdc12af5025e (diff) | |
riscv: kprobes: Fix incorrect address calculation
p->ainsn.api.insn is a pointer to u32, therefore arithmetic operations are
multiplied by four. This is clearly undesirable for this case.
Cast it to (void *) first before any calculation.
Below is a sample before/after. The dumped memory is two kprobe slots, the
first slot has
- c.addiw a0, 0x1c (0x7125)
- ebreak (0x00100073)
and the second slot has:
- c.addiw a0, -4 (0x7135)
- ebreak (0x00100073)
Before this patch:
(gdb) x/16xh 0xff20000000135000
0xff20000000135000: 0x7125 0x0000 0x0000 0x0000 0x7135 0x0010 0x0000 0x0000
0xff20000000135010: 0x0073 0x0010 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
After this patch:
(gdb) x/16xh 0xff20000000125000
0xff20000000125000: 0x7125 0x0073 0x0010 0x0000 0x7135 0x0073 0x0010 0x0000
0xff20000000125010: 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000
Fixes: b1756750a397 ("riscv: kprobes: Use patch_text_nosync() for insn slots")
Signed-off-by: Nam Cao <[email protected]>
Cc: [email protected]
Reviewed-by: Alexandre Ghiti <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>
| -rw-r--r-- | arch/riscv/kernel/probes/kprobes.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c index 380a0e8cecc0..c0738d6c6498 100644 --- a/arch/riscv/kernel/probes/kprobes.c +++ b/arch/riscv/kernel/probes/kprobes.c @@ -30,7 +30,7 @@ static void __kprobes arch_prepare_ss_slot(struct kprobe *p) p->ainsn.api.restore = (unsigned long)p->addr + len; patch_text_nosync(p->ainsn.api.insn, &p->opcode, len); - patch_text_nosync(p->ainsn.api.insn + len, &insn, GET_INSN_LENGTH(insn)); + patch_text_nosync((void *)p->ainsn.api.insn + len, &insn, GET_INSN_LENGTH(insn)); } static void __kprobes arch_prepare_simulate(struct kprobe *p) |