ftrace/x86_32: Set ftrace_stub to weak to prevent gcc from using short jumps to it

2017-06-17T13:47:45+00:00

commit 847fa1a6d3d00f3bdf68ef5fa4a786f644a0dd67 upstream. With new binutils, gcc may get smart with its optimization and change a jmp from a 5 byte jump to a 2 byte one even though it was jumping to a global function. But that global function existed within a 2 byte radius, and gcc was able to optimize it. Unfortunately, that jump was also being modified when function graph tracing begins. Since ftrace expected that jump to be 5 bytes, but it was only two, it overwrote code after the jump, causing a crash. This was fixed for x86_64 with commit 8329e818f149, with the same subject as this commit, but nothing was done for x86_32. Fixes: d61f82d06672 ("ftrace: use dynamic patching for updating mcount calls") Reported-by: Colin Ian King Tested-by: Colin Ian King Signed-off-by: Steven Rostedt Signed-off-by: Willy Tarreau

first commit

2016-08-15T02:19:42+00:00

xavi/android_kernel_m2note/arch/x86/kernel/entry_32.S, branch ng-7.1.2

ftrace/x86_32: Set ftrace_stub to weak to prevent gcc from using short jumps to it

first commit