From: Johannes Berg johannes.berg@intel.com
commit 675751bb20634f981498c7d66161584080cc061e upstream.
If something was written to the buffer just before destruction, it may be possible (maybe not in a real system, but it did happen in ARCH=um with time-travel) to destroy the ringbuffer before the IRQ work ran, leading this KASAN report (or a crash without KASAN):
BUG: KASAN: slab-use-after-free in irq_work_run_list+0x11a/0x13a Read of size 8 at addr 000000006d640a48 by task swapper/0
CPU: 0 PID: 0 Comm: swapper Tainted: G W O 6.3.0-rc1 #7 Stack: 60c4f20f 0c203d48 41b58ab3 60f224fc 600477fa 60f35687 60c4f20f 601273dd 00000008 6101eb00 6101eab0 615be548 Call Trace: [<60047a58>] show_stack+0x25e/0x282 [<60c609e0>] dump_stack_lvl+0x96/0xfd [<60c50d4c>] print_report+0x1a7/0x5a8 [<603078d3>] kasan_report+0xc1/0xe9 [<60308950>] __asan_report_load8_noabort+0x1b/0x1d [<60232844>] irq_work_run_list+0x11a/0x13a [<602328b4>] irq_work_tick+0x24/0x34 [<6017f9dc>] update_process_times+0x162/0x196 [<6019f335>] tick_sched_handle+0x1a4/0x1c3 [<6019fd9e>] tick_sched_timer+0x79/0x10c [<601812b9>] __hrtimer_run_queues.constprop.0+0x425/0x695 [<60182913>] hrtimer_interrupt+0x16c/0x2c4 [<600486a3>] um_timer+0x164/0x183 [...]
Allocated by task 411: save_stack_trace+0x99/0xb5 stack_trace_save+0x81/0x9b kasan_save_stack+0x2d/0x54 kasan_set_track+0x34/0x3e kasan_save_alloc_info+0x25/0x28 ____kasan_kmalloc+0x8b/0x97 __kasan_kmalloc+0x10/0x12 __kmalloc+0xb2/0xe8 load_elf_phdrs+0xee/0x182 [...]
The buggy address belongs to the object at 000000006d640800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 584 bytes inside of freed 1024-byte region [000000006d640800, 000000006d640c00)
Add the appropriate irq_work_sync() so the work finishes before the buffers are destroyed.
Prior to the commit in the Fixes tag below, there was only a single global IRQ work, so this issue didn't exist.
Link: https://lore.kernel.org/linux-trace-kernel/20230427175920.a76159263122.I8295...
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Fixes: 15693458c4bc ("tracing/ring-buffer: Move poll wake ups into ring buffer code") Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/ring_buffer.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1393,6 +1393,8 @@ static void rb_free_cpu_buffer(struct ri struct list_head *head = cpu_buffer->pages; struct buffer_page *bpage, *tmp;
+ irq_work_sync(&cpu_buffer->irq_work.work); + free_buffer_page(cpu_buffer->reader_page);
if (head) { @@ -1498,6 +1500,8 @@ ring_buffer_free(struct ring_buffer *buf
cpuhp_state_remove_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
+ irq_work_sync(&buffer->irq_work.work); + for_each_buffer_cpu(buffer, cpu) rb_free_cpu_buffer(buffer->buffers[cpu]);