On Mon, Feb 02, 2026 at 10:58:27AM +0100, Arnd Bergmann wrote: > The sunrpc change to use trace_printk() for debugging caused > a new warning for every instance of dprintk() in some configurations, > when -Wformat-security is enabled: > > fs/nfs/getroot.c: In function 'nfs_get_root': > fs/nfs/getroot.c:90:17: error: format not a string literal and no format > arguments [-Werror=format-security] > 90 | nfs_errorf(fc, "NFS: Couldn't getattr on root"); > > I've been slowly chipping away at those warnings over time with the > intention of enabling them by default in the future. While I could not > figure out why this only happens for this one instance, I see that the > __trace_bprintk() function is always called with a local variable as > the format string, rather than a literal. > > Remove the __printf(2,3) annotation on this function, as this is can > only be validated for literals. The format strings still get checked > because the underlying literal keeps getting passed into __trace_printk() > in the "else" branch, which is not taken but still evaluated for > compile-time warnings.
Yeah, it was discussed in the past that binary printf() should not be annotated as we have BPF code that doesn't compile (with the default WERROR=y). -- With Best Regards, Andy Shevchenko
