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13134cc949
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: b1756750a3 ("riscv: kprobes: Use patch_text_nosync() for insn slots")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20241119111056.2554419-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.