From: Steven Rostedt (VMware) Date: Wed, 11 Dec 2019 20:44:22 +0000 (-0500) Subject: tracing: Have the histogram compare functions convert to u64 first X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=70f32bb7bdb885c9ef2a1b1076b52c81927bb31a;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git tracing: Have the histogram compare functions convert to u64 first commit 106f41f5a302cb1f36c7543fae6a05de12e96fa4 upstream. The compare functions of the histogram code would be specific for the size of the value being compared (byte, short, int, long long). It would reference the value from the array via the type of the compare, but the value was stored in a 64 bit number. This is fine for little endian machines, but for big endian machines, it would end up comparing zeros or all ones (depending on the sign) for anything but 64 bit numbers. To fix this, first derference the value as a u64 then convert it to the type being compared. Link: http://lkml.kernel.org/r/20191211103557.7bed6928@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 08d43a5fa063e ("tracing: Add lock-free tracing_map") Acked-by: Tom Zanussi Reported-by: Sven Schnelle Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 305039b122fa..35b2ba07f3c6 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -90,8 +90,8 @@ static int tracing_map_cmp_atomic64(void *val_a, void *val_b) #define DEFINE_TRACING_MAP_CMP_FN(type) \ static int tracing_map_cmp_##type(void *val_a, void *val_b) \ { \ - type a = *(type *)val_a; \ - type b = *(type *)val_b; \ + type a = (type)(*(u64 *)val_a); \ + type b = (type)(*(u64 *)val_b); \ \ return (a > b) ? 1 : ((a < b) ? -1 : 0); \ }