On Tue, Mar 12, 2024 at 05:42:33PM +0800, George Guo wrote:
> From: George Guo <guodongtai@xxxxxxxxxx>
>
> The onmax_destroy() destroyed the onmax var, casusing a double-free error
> flagged by KASAN.
>
> This is tested via "./ftracetest test.d/trigger/inter-event/
> trigger-onmatch-onmax-action-hist.tc".
>
> ==================================================================
> BUG: KASAN: use-after-free in destroy_hist_field+0x1c2/0x200
> Read of size 8 at addr ffff88800a4ad100 by task ftracetest/4731
>
> CPU: 0 PID: 4731 Comm: ftracetest Kdump: loaded Tainted: GE 4.19.90-89 #77
> 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+0x1c2/0x200
> ? hist_trigger_elt_data_alloc+0x5a0/0x5a0
> __asan_report_load8_noabort+0x8d/0xa0
> ? destroy_hist_field+0x1c2/0x200
> destroy_hist_field+0x1c2/0x200
> onmax_destroy+0x72/0x1e0
> ? hist_trigger_elt_data_alloc+0x5a0/0x5a0
> destroy_hist_data+0x236/0xa40
> 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_cmp_u64+0xa0/0xa0
> ? onmatch_create.constprop.0+0xf50/0xf50
> ? __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: 0033:0x7fd7f4c44e04
> 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:00007fff10370df8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 000000000000010f RCX: 00007fd7f4c44e04
> RDX: 000000000000010f RSI: 000055fa765df650 RDI: 0000000000000001
> RBP: 000055fa765df650 R08: 000000000000000a R09: 0000000000000000
> R10: 000000000000000a R11: 0000000000000246 R12: 00007fd7f4d035c0
> R13: 000000000000010f R14: 00007fd7f4d037c0 R15: 000000000000010f
> ==================================================================
>
> So remove the onmax_destroy() destroy_hist_field() call for that var.
>
> Fixes: 50450603ec9c("tracing: Add 'onmax' hist trigger action support")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: George Guo <guodongtai@xxxxxxxxxx>
> ---
> kernel/trace/trace_events_hist.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 7dcb96305e56..58b8a2575b8c 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -337,7 +337,6 @@ struct action_data {
> char *fn_name;
> unsigned int max_var_ref_idx;
> struct hist_field *max_var;
> - struct hist_field *var;
> } onmax;
> };
> };
> @@ -3489,7 +3488,6 @@ static void onmax_destroy(struct action_data *data)
> unsigned int i;
>
> destroy_hist_field(data->onmax.max_var, 0);
> - destroy_hist_field(data->onmax.var, 0);
>
> kfree(data->onmax.var_str);
> kfree(data->onmax.fn_name);
> @@ -3528,8 +3526,6 @@ static int onmax_create(struct hist_trigger_data *hist_data,
> if (!ref_field)
> return -ENOMEM;
>
> - data->onmax.var = ref_field;
> -
> data->fn = onmax_save;
> data->onmax.max_var_ref_idx = var_ref_idx;
> max_var = create_var(hist_data, file, "max", sizeof(u64), "u64");
> --
> 2.34.1
>
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
