| Message ID | 20210912160149.2227137-5-linux@roeck-us.net |
|---|---|
| State | New |
| Headers | show |
| Series | Introduce and use absolute_pointer macro | expand |
On Sun, Sep 12, 2021 at 9:02 AM Guenter Roeck <linux@roeck-us.net> wrote: > > - if (strcmp(COMMAND_LINE, "INSTALL") == 0) { > + if (strcmp(absolute_pointer(COMMAND_LINE), "INSTALL") == 0) { Again, this feels very much like treating the symptoms, not actually fixing the real issue. It's COMMAND_LINE itself that should have been fixed up, not that one use of it. Because the only reason you didn't get a warning from later uses is that 'strcmp()' is doing compiler-specific magic. You're just delaying the inevitable warnings about the other uses of that thing. Linus
On 9/12/21 12:13 PM, Linus Torvalds wrote: > On Sun, Sep 12, 2021 at 9:02 AM Guenter Roeck <linux@roeck-us.net> wrote: >> >> - if (strcmp(COMMAND_LINE, "INSTALL") == 0) { >> + if (strcmp(absolute_pointer(COMMAND_LINE), "INSTALL") == 0) { > > Again, this feels very much like treating the symptoms, not actually > fixing the real issue. > > It's COMMAND_LINE itself that should have been fixed up, not that one use of it. > > Because the only reason you didn't get a warning from later uses is > that 'strcmp()' is doing compiler-specific magic. You're just delaying > the inevitable warnings about the other uses of that thing. > COMMAND_LINE is, for whatever reason, defined in arch/alpha/include/uapi/asm/setup.h, ie in the uapi. Can I even touch that ? Guenter
diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c index b4fbbba30aa2..aab477a76c30 100644 --- a/arch/alpha/kernel/setup.c +++ b/arch/alpha/kernel/setup.c @@ -490,7 +490,7 @@ setup_arch(char **cmdline_p) /* Hack for Jensen... since we're restricted to 8 or 16 chars for boot flags depending on the boot mode, we need some shorthand. This should do for installation. */ - if (strcmp(COMMAND_LINE, "INSTALL") == 0) { + if (strcmp(absolute_pointer(COMMAND_LINE), "INSTALL") == 0) { strlcpy(command_line, "root=/dev/fd0 load_ramdisk=1", sizeof command_line); } else { strlcpy(command_line, COMMAND_LINE, sizeof command_line);
alpha:allmodconfig fails to build with the following error when using gcc 11.x. arch/alpha/kernel/setup.c: In function 'setup_arch': arch/alpha/kernel/setup.c:493:13: error: 'strcmp' reading 1 or more bytes from a region of size 0 Avoid the problem by using absolute_pointer() when providing a memory address to strcmp(). Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- arch/alpha/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)