| Message ID | 20230320230534.50174-1-bgray@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | init/initramfs: Fix argument forwarding to panic() in panic_show_mem() | expand |
On Tue, 2023-03-21 at 10:05 +1100, Benjamin Gray wrote: > Forwarding variadic argument lists can't be done by passing a va_list > to a function with signature foo(...) (as panic() has). It ends up > interpreting the va_list itself as a single argument instead of > iterating it. printf() happily accepts it of course, leading to > corrupt > output. > > Convert panic_show_mem() to a macro to allow forwarding the > arguments. > The function is trivial enough that it's easier than trying to > introduce > a vpanic() variant. > > Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
On Tue, Mar 21, 2023 at 8:06 AM Benjamin Gray <bgray@linux.ibm.com> wrote: > > Forwarding variadic argument lists can't be done by passing a va_list > to a function with signature foo(...) (as panic() has). It ends up > interpreting the va_list itself as a single argument instead of > iterating it. printf() happily accepts it of course, leading to corrupt > output. > > Convert panic_show_mem() to a macro to allow forwarding the arguments. > The function is trivial enough that it's easier than trying to introduce > a vpanic() variant. > > Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> Applied to linux-kbuild. Thanks. > > --- > > After sending these patches [1] I wondered why the kernel accepted a > corrupt archive. The streaming parser makes it difficult to see > where to add a completeness check (possibly can assert the state is > Start or Reset at the end?), but adding an error() to cover my issue > revealed that the error message was never printed. > > [1]: https://lore.kernel.org/all/20230320040839.660475-1-bgray@linux.ibm.com/ > --- > init/initramfs.c | 11 ++--------- > 1 file changed, 2 insertions(+), 9 deletions(-) > > diff --git a/init/initramfs.c b/init/initramfs.c > index f6c112e30bd4..e7a01c2ccd1b 100644 > --- a/init/initramfs.c > +++ b/init/initramfs.c > @@ -60,15 +60,8 @@ static void __init error(char *x) > message = x; > } > > -static void panic_show_mem(const char *fmt, ...) > -{ > - va_list args; > - > - show_mem(0, NULL); > - va_start(args, fmt); > - panic(fmt, args); > - va_end(args); > -} > +#define panic_show_mem(fmt, ...) \ > + ({ show_mem(0, NULL); panic(fmt, ##__VA_ARGS__); }) > > /* link hash */ > > > base-commit: 065ffaee73892e8a3629b4cfbe635697807a3c6f > prerequisite-patch-id: 6e3cfc6bf9c5686ad29c7feed8e283d30b1957fd > prerequisite-patch-id: 933a7bd2f29223dba7f2cac7e9aa72aae730292d > -- > 2.39.2 >
diff --git a/init/initramfs.c b/init/initramfs.c index f6c112e30bd4..e7a01c2ccd1b 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -60,15 +60,8 @@ static void __init error(char *x) message = x; } -static void panic_show_mem(const char *fmt, ...) -{ - va_list args; - - show_mem(0, NULL); - va_start(args, fmt); - panic(fmt, args); - va_end(args); -} +#define panic_show_mem(fmt, ...) \ + ({ show_mem(0, NULL); panic(fmt, ##__VA_ARGS__); }) /* link hash */
Forwarding variadic argument lists can't be done by passing a va_list to a function with signature foo(...) (as panic() has). It ends up interpreting the va_list itself as a single argument instead of iterating it. printf() happily accepts it of course, leading to corrupt output. Convert panic_show_mem() to a macro to allow forwarding the arguments. The function is trivial enough that it's easier than trying to introduce a vpanic() variant. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> --- After sending these patches [1] I wondered why the kernel accepted a corrupt archive. The streaming parser makes it difficult to see where to add a completeness check (possibly can assert the state is Start or Reset at the end?), but adding an error() to cover my issue revealed that the error message was never printed. [1]: https://lore.kernel.org/all/20230320040839.660475-1-bgray@linux.ibm.com/ --- init/initramfs.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) base-commit: 065ffaee73892e8a3629b4cfbe635697807a3c6f prerequisite-patch-id: 6e3cfc6bf9c5686ad29c7feed8e283d30b1957fd prerequisite-patch-id: 933a7bd2f29223dba7f2cac7e9aa72aae730292d