[PATCH 4.19.y v5 0/2] Double-free bug discovery on testing trigger-field-variable-support.tc
1) About v4-0001-tracing-Remove-hist-trigger-synth_var_refs.patch:
The reason I am backporting this patch is that no one found the double-free bug at that time, then later the code was removed on upstream, but 4.19-stable has the bug.
This is tested via "./ftracetest test.d/trigger/inter-event/ trigger-field-variable-support.tc" ================================================================== BUG: KASAN: use-after-free in destroy_hist_field+0x115/0x140 Read of size 4 at addr ffff888012e95318 by task ftracetest/1858
CPU: 1 PID: 1858 Comm: ftracetest Kdump: loaded Tainted: GE 4.19.90-89 #24 Source Version: Unknown Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0 Call Trace: dump_stack+0xcb/0x10b print_address_description.cold+0x54/0x249 kasan_report_error.cold+0x63/0xab ? destroy_hist_field+0x115/0x140 __asan_report_load4_noabort+0x8d/0xa0 ? destroy_hist_field+0x115/0x140 destroy_hist_field+0x115/0x140 destroy_hist_data+0x4e4/0x9a0 event_hist_trigger_free+0x212/0x2f0 ? update_cond_flag+0x128/0x170 ? event_hist_trigger_func+0x2880/0x2880 hist_unregister_trigger+0x2f2/0x4f0 event_hist_trigger_func+0x168c/0x2880 ? tracing_map_read_var_once+0xd0/0xd0 ? create_key_field+0x520/0x520 ? __mutex_lock_slowpath+0x10/0x10 event_trigger_write+0x2f4/0x490 ? trigger_start+0x180/0x180 ? __fget_light+0x369/0x5d0 ? count_memcg_event_mm+0x104/0x2b0 ? trigger_start+0x180/0x180 __vfs_write+0x81/0x100 vfs_write+0x1e1/0x540 ksys_write+0x12a/0x290 ? __ia32_sys_read+0xb0/0xb0 ? __close_fd+0x1d3/0x280 do_syscall_64+0xe3/0x2d0 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7efdd342ee04 Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 39 34 0c 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5 RSP: 002b:00007ffda01f5e08 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000000000b4 RCX: 00007efdd342ee04 RDX: 00000000000000b4 RSI: 000055c5b41b1e90 RDI: 0000000000000001 RBP: 000055c5b41b1e90 R08: 000000000000000a R09: 0000000000000000 R10: 000000000000000a R11: 0000000000000246 R12: 00007efdd34ed5c0 R13: 00000000000000b4 R14: 00007efdd34ed7c0 R15: 00000000000000b4 ==================================================================
2) About v4-0002-tracing-Use-var_refs-for-hist-trigger-reference-c.patch:
Only v4-0001-tracing-Remove-hist-trigger-synth_var_refs.patch will lead to compilation errors:
../kernel/trace/trace_events_hist.c: In function ���find_var_ref���: ../kernel/trace/trace_events_hist.c:1364:36: error: ���struct hist_trigger_data��� has no member named ���n_synth_var_refs���; did you mean ���n_var_refs���? 1364 | for (i = 0; i < hist_data->n_synth_var_refs; i++) { | ^~~~~~~~~~~~~~~~ | n_var_refs ../kernel/trace/trace_events_hist.c:1365:41: error: ���struct hist_trigger_data��� has no member named ���synth_var_refs���; did you mean ���n_var_refs���? 1365 | hist_field = hist_data->synth_var_refs[i]; | ^~~~~~~~~~~~~~ | n_var_refs
3) Singing off my name on the V5.
Tom Zanussi (2): tracing: Remove hist trigger synth_var_refs tracing: Use var_refs[] for hist trigger reference checking
kernel/trace/trace_events_hist.c | 86 ++++---------------------------- 1 file changed, 11 insertions(+), 75 deletions(-)
From: Tom Zanussi tom.zanussi@linux.intel.com
All var_refs are now handled uniformly and there's no reason to treat the synth_refs in a special way now, so remove them and associated functions.
Link: http://lkml.kernel.org/r/b4d3470526b8f0426dcec125399dad9ad9b8589d.1545161087...
Acked-by: Namhyung Kim namhyung@kernel.org Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Tom Zanussi tom.zanussi@linux.intel.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: George Guo guodongtai@kylinos.cn --- kernel/trace/trace_events_hist.c | 18 ------------------ 1 file changed, 18 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index e004daf8cad5..e4f5b6894cf2 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -280,8 +280,6 @@ struct hist_trigger_data { struct action_data *actions[HIST_ACTIONS_MAX]; unsigned int n_actions;
- struct hist_field *synth_var_refs[SYNTH_FIELDS_MAX]; - unsigned int n_synth_var_refs; struct field_var *field_vars[SYNTH_FIELDS_MAX]; unsigned int n_field_vars; unsigned int n_field_var_str; @@ -3708,20 +3706,6 @@ static void save_field_var(struct hist_trigger_data *hist_data, }
-static void destroy_synth_var_refs(struct hist_trigger_data *hist_data) -{ - unsigned int i; - - for (i = 0; i < hist_data->n_synth_var_refs; i++) - destroy_hist_field(hist_data->synth_var_refs[i], 0); -} - -static void save_synth_var_ref(struct hist_trigger_data *hist_data, - struct hist_field *var_ref) -{ - hist_data->synth_var_refs[hist_data->n_synth_var_refs++] = var_ref; -} - static int check_synth_field(struct synth_event *event, struct hist_field *hist_field, unsigned int field_pos) @@ -3884,7 +3868,6 @@ static int onmatch_create(struct hist_trigger_data *hist_data, goto err; }
- save_synth_var_ref(hist_data, var_ref); field_pos++; kfree(p); continue; @@ -4631,7 +4614,6 @@ static void destroy_hist_data(struct hist_trigger_data *hist_data) destroy_actions(hist_data); destroy_field_vars(hist_data); destroy_field_var_hists(hist_data); - destroy_synth_var_refs(hist_data);
kfree(hist_data); }
On Tue, Apr 16, 2024 at 09:54:31AM +0800, George Guo wrote:
From: Tom Zanussi tom.zanussi@linux.intel.com
All var_refs are now handled uniformly and there's no reason to treat the synth_refs in a special way now, so remove them and associated functions.
Link: http://lkml.kernel.org/r/b4d3470526b8f0426dcec125399dad9ad9b8589d.1545161087...
Acked-by: Namhyung Kim namhyung@kernel.org Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Tom Zanussi tom.zanussi@linux.intel.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: George Guo guodongtai@kylinos.cn
kernel/trace/trace_events_hist.c | 18 ------------------ 1 file changed, 18 deletions(-)
What is the git commit id of this change in Linus's tree? Always include that please.
Can you fix up and resend the series?
thanks,
greg k-h
From: Tom Zanussi tzanussi@gmail.com
Since all the variable reference hist_fields are collected into hist_data->var_refs[] array, there's no need to go through all the fields looking for them, or in separate arrays like synth_var_refs[], which will be going away soon anyway.
This also allows us to get rid of some unnecessary code and functions currently used for the same purpose.
Link: http://lkml.kernel.org/r/1545246556.4239.7.camel@gmail.com
Acked-by: Namhyung Kim namhyung@kernel.org Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Tom Zanussi tom.zanussi@linux.intel.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: George Guo guodongtai@kylinos.cn --- kernel/trace/trace_events_hist.c | 68 ++++++-------------------------- 1 file changed, 11 insertions(+), 57 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index e4f5b6894cf2..ede370225245 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1289,49 +1289,13 @@ check_field_for_var_ref(struct hist_field *hist_field, struct hist_trigger_data *var_data, unsigned int var_idx) { - struct hist_field *found = NULL; - - if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF) { - if (hist_field->var.idx == var_idx && - hist_field->var.hist_data == var_data) { - found = hist_field; - } - } - - return found; -} - -static struct hist_field * -check_field_for_var_refs(struct hist_trigger_data *hist_data, - struct hist_field *hist_field, - struct hist_trigger_data *var_data, - unsigned int var_idx, - unsigned int level) -{ - struct hist_field *found = NULL; - unsigned int i; - - if (level > 3) - return found; - - if (!hist_field) - return found; - - found = check_field_for_var_ref(hist_field, var_data, var_idx); - if (found) - return found; - - for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) { - struct hist_field *operand; + WARN_ON(!(hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF));
- operand = hist_field->operands[i]; - found = check_field_for_var_refs(hist_data, operand, var_data, - var_idx, level + 1); - if (found) - return found; - } + if (hist_field && hist_field->var.idx == var_idx && + hist_field->var.hist_data == var_data) + return hist_field;
- return found; + return NULL; }
/** @@ -1350,26 +1314,16 @@ static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data, struct hist_trigger_data *var_data, unsigned int var_idx) { - struct hist_field *hist_field, *found = NULL; + struct hist_field *hist_field; unsigned int i;
- for_each_hist_field(i, hist_data) { - hist_field = hist_data->fields[i]; - found = check_field_for_var_refs(hist_data, hist_field, - var_data, var_idx, 0); - if (found) - return found; - } - - for (i = 0; i < hist_data->n_synth_var_refs; i++) { - hist_field = hist_data->synth_var_refs[i]; - found = check_field_for_var_refs(hist_data, hist_field, - var_data, var_idx, 0); - if (found) - return found; + for (i = 0; i < hist_data->n_var_refs; i++) { + hist_field = hist_data->var_refs[i]; + if (check_field_for_var_ref(hist_field, var_data, var_idx)) + return hist_field; }
- return found; + return NULL; }
/**
linux-stable-mirror@lists.linaro.org
-
George Guo -
Greg KH