From 7f904ff6e58d398c4336f3c19c42b338324451f7 Mon Sep 17 00:00:00 2001 From: Gabriele Monaco Date: Mon, 28 Jul 2025 15:50:15 +0200 Subject: [PATCH] rv: Use strings in da monitors tracepoints Using DA monitors tracepoints with KASAN enabled triggers the following warning: BUG: KASAN: global-out-of-bounds in do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0 Read of size 32 at addr ffffffffaada8980 by task ... Call Trace: [...] do_trace_event_raw_event_event_da_monitor+0xd6/0x1a0 ? __pfx_do_trace_event_raw_event_event_da_monitor+0x10/0x10 ? trace_event_sncid+0x83/0x200 trace_event_sncid+0x163/0x200 [...] The buggy address belongs to the variable: automaton_snep+0x4e0/0x5e0 This is caused by the tracepoints reading 32 bytes __array instead of __string from the automata definition. Such strings are literals and reading 32 bytes ends up in out of bound memory accesses (e.g. the next automaton's data in this case). The error is harmless as, while printing the string, we stop at the null terminator, but it should still be fixed. Use the __string facilities while defining the tracepoints to avoid reading out of bound memory. Cc: Masami Hiramatsu Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Tomas Glozar Cc: Juri Lelli Cc: Clark Williams Cc: John Kacur Link: https://lore.kernel.org/20250728135022.255578-4-gmonaco@redhat.com Fixes: 792575348ff7 ("rv/include: Add deterministic automata monitor definition via C macros") Reviewed-by: Nam Cao Signed-off-by: Gabriele Monaco Signed-off-by: Steven Rostedt (Google) --- kernel/trace/rv/rv_trace.h | 76 +++++++++++++++++++------------------- 1 file changed, 38 insertions(+), 38 deletions(-) diff --git a/kernel/trace/rv/rv_trace.h b/kernel/trace/rv/rv_trace.h index 17ba07329b67..d38e0d3abdfd 100644 --- a/kernel/trace/rv/rv_trace.h +++ b/kernel/trace/rv/rv_trace.h @@ -16,23 +16,23 @@ DECLARE_EVENT_CLASS(event_da_monitor, TP_ARGS(state, event, next_state, final_state), TP_STRUCT__entry( - __array( char, state, MAX_DA_NAME_LEN ) - __array( char, event, MAX_DA_NAME_LEN ) - __array( char, next_state, MAX_DA_NAME_LEN ) - __field( bool, final_state ) + __string( state, state ) + __string( event, event ) + __string( next_state, next_state ) + __field( bool, final_state ) ), TP_fast_assign( - memcpy(__entry->state, state, MAX_DA_NAME_LEN); - memcpy(__entry->event, event, MAX_DA_NAME_LEN); - memcpy(__entry->next_state, next_state, MAX_DA_NAME_LEN); - __entry->final_state = final_state; + __assign_str(state); + __assign_str(event); + __assign_str(next_state); + __entry->final_state = final_state; ), TP_printk("%s x %s -> %s%s", - __entry->state, - __entry->event, - __entry->next_state, + __get_str(state), + __get_str(event), + __get_str(next_state), __entry->final_state ? " (final)" : "") ); @@ -43,18 +43,18 @@ DECLARE_EVENT_CLASS(error_da_monitor, TP_ARGS(state, event), TP_STRUCT__entry( - __array( char, state, MAX_DA_NAME_LEN ) - __array( char, event, MAX_DA_NAME_LEN ) + __string( state, state ) + __string( event, event ) ), TP_fast_assign( - memcpy(__entry->state, state, MAX_DA_NAME_LEN); - memcpy(__entry->event, event, MAX_DA_NAME_LEN); + __assign_str(state); + __assign_str(event); ), TP_printk("event %s not expected in the state %s", - __entry->event, - __entry->state) + __get_str(event), + __get_str(state)) ); #include @@ -75,26 +75,26 @@ DECLARE_EVENT_CLASS(event_da_monitor_id, TP_ARGS(id, state, event, next_state, final_state), TP_STRUCT__entry( - __field( int, id ) - __array( char, state, MAX_DA_NAME_LEN ) - __array( char, event, MAX_DA_NAME_LEN ) - __array( char, next_state, MAX_DA_NAME_LEN ) - __field( bool, final_state ) + __field( int, id ) + __string( state, state ) + __string( event, event ) + __string( next_state, next_state ) + __field( bool, final_state ) ), TP_fast_assign( - memcpy(__entry->state, state, MAX_DA_NAME_LEN); - memcpy(__entry->event, event, MAX_DA_NAME_LEN); - memcpy(__entry->next_state, next_state, MAX_DA_NAME_LEN); - __entry->id = id; - __entry->final_state = final_state; + __assign_str(state); + __assign_str(event); + __assign_str(next_state); + __entry->id = id; + __entry->final_state = final_state; ), TP_printk("%d: %s x %s -> %s%s", __entry->id, - __entry->state, - __entry->event, - __entry->next_state, + __get_str(state), + __get_str(event), + __get_str(next_state), __entry->final_state ? " (final)" : "") ); @@ -105,21 +105,21 @@ DECLARE_EVENT_CLASS(error_da_monitor_id, TP_ARGS(id, state, event), TP_STRUCT__entry( - __field( int, id ) - __array( char, state, MAX_DA_NAME_LEN ) - __array( char, event, MAX_DA_NAME_LEN ) + __field( int, id ) + __string( state, state ) + __string( event, event ) ), TP_fast_assign( - memcpy(__entry->state, state, MAX_DA_NAME_LEN); - memcpy(__entry->event, event, MAX_DA_NAME_LEN); - __entry->id = id; + __assign_str(state); + __assign_str(event); + __entry->id = id; ), TP_printk("%d: event %s not expected in the state %s", __entry->id, - __entry->event, - __entry->state) + __get_str(event), + __get_str(state)) ); #include -- 2.25.1