| Message ID | 20250108090457.512198-22-bigeasy@linutronix.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | module: Use RCU instead of RCU-sched. | expand |
| Context | Check | Description |
|---|---|---|
| mcgrof/vmtest-modules-next-PR | fail | PR summary |
| mcgrof/vmtest-modules-next-VM_Test-0 | success | Logs for Run CI tests |
| mcgrof/vmtest-modules-next-VM_Test-2 | success | Logs for setup / Setup kdevops environment |
| mcgrof/vmtest-modules-next-VM_Test-1 | success | Logs for cleanup / Archive results and cleanup |
diff --git a/kernel/cfi.c b/kernel/cfi.c index 08caad7767176..abcd4d1f98eab 100644 --- a/kernel/cfi.c +++ b/kernel/cfi.c @@ -71,14 +71,11 @@ static bool is_module_cfi_trap(unsigned long addr) struct module *mod; bool found = false; - rcu_read_lock_sched_notrace(); - + guard(rcu)(); mod = __module_address(addr); if (mod) found = is_trap(addr, mod->kcfi_traps, mod->kcfi_traps_end); - rcu_read_unlock_sched_notrace(); - return found; } #else /* CONFIG_MODULES */
__module_address() can be invoked within a RCU section, there is no requirement to have preemption disabled. The _notrace() variant was introduced in commit 14c4c8e41511a ("cfi: Use rcu_read_{un}lock_sched_notrace"). The recursive case where __cfi_slowpath_diag() could end up calling itself is no longer present, as all that logic is gone since commit 89245600941e ("cfi: Switch to -fsanitize=kcfi"). Sami Tolvanen said that KCFI checks don't perform function calls. Elliot Berman verified it with | modprobe -a dummy_stm stm_ftrace stm_p_basic | mkdir -p /sys/kernel/config/stp-policy/dummy_stm.0.my-policy/default | echo function > /sys/kernel/tracing/current_tracer | echo 1 > /sys/kernel/tracing/tracing_on | echo dummy_stm.0 > /sys/class/stm_source/ftrace/stm_source_link Replace the rcu_read_lock_sched_notrace() section around __module_address() with RCU. Cc: Elliot Berman <quic_eberman@quicinc.com> Cc: Kees Cook <kees@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: llvm@lists.linux.dev Tested-by: Elliot Berman <elliot.berman@oss.qualcomm.com> # sm8650-qrd Link: https://lore.kernel.org/all/20241230185812429-0800.eberman@hu-eberman-lv.qualcomm.com Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- kernel/cfi.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)