Commit 7dfbfb87c243 ("powerpc/ftrace: Activate
HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") made count_relocs()
undercount the PLT entries the loader
consumes: module_finalize_ftrace() now creates two trampolines
(mod->arch.tramp for ftrace_caller() and mod->arch.tramp_regs for
ftrace_regs_caller()), while count_relocs() reserves only one entry
for ftrace.So the core .plt ends up one ppc_plt_entry (16 bytes) short. The walk in do_plt_call() scans for a free slot with "while (entry->jump[0])" and has no bound check, so once the last reserved slot is used up, the walk steps past the end of the section and patch_instruction() writes the 4-instruction trampoline into whatever module memory follows the .plt. Count the second entry, mirroring what module_64.c does for the same pair of stubs. Signed-off-by: Bradley Morgan <[email protected]> --- arch/powerpc/kernel/module_32.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c index f930e3395a7f..61152deffc55 100644 --- a/arch/powerpc/kernel/module_32.c +++ b/arch/powerpc/kernel/module_32.c @@ -41,6 +41,9 @@ static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num) #ifdef CONFIG_DYNAMIC_FTRACE _count_relocs++; /* add one for ftrace_caller */ +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + _count_relocs++; /* add one for ftrace_regs_caller */ +#endif #endif return _count_relocs; } -- 2.53.0
