On Tue, Jan 09, 2024 at 10:17:22AM -0800, John Sperbeck wrote:
> With 5.10LTS (e.g., 5.10.206), on a machine using an NVME device, the
> following tracing commands will trigger a crash due to a NULL pointer
> dereference:
>
> KDIR=/sys/kernel/debug/tracing
> echo 1 > $KDIR/tracing_on
> echo 1 > $KDIR/events/nvme/enable
> echo "Waiting for trace events..."
> cat $KDIR/trace_pipe
>
> The backtrace looks something like this:
>
> Call Trace:
> <IRQ>
> ? __die_body+0x6b/0xb0
> ? __die+0x9e/0xb0
> ? no_context+0x3eb/0x460
> ? ttwu_do_activate+0xf0/0x120
> ? __bad_area_nosemaphore+0x157/0x200
> ? select_idle_sibling+0x2f/0x410
> ? bad_area_nosemaphore+0x13/0x20
> ? do_user_addr_fault+0x2ab/0x360
> ? exc_page_fault+0x69/0x180
> ? asm_exc_page_fault+0x1e/0x30
> ? trace_event_raw_event_nvme_complete_rq+0xba/0x170
> ? trace_event_raw_event_nvme_complete_rq+0xa3/0x170
> nvme_complete_rq+0x168/0x170
> nvme_pci_complete_rq+0x16c/0x1f0
> nvme_handle_cqe+0xde/0x190
> nvme_irq+0x78/0x100
> __handle_irq_event_percpu+0x77/0x1e0
> handle_irq_event+0x54/0xb0
> handle_edge_irq+0xdf/0x230
> asm_call_irq_on_stack+0xf/0x20
> </IRQ>
> common_interrupt+0x9e/0x150
> asm_common_interrupt+0x1e/0x40
>
> It looks to me like these two upstream commits were backported to 5.10:
>
> 679c54f2de67 ("nvme: use command_id instead of req->tag in trace_nvme_complete_rq()")
> e7006de6c238 ("nvme: code command_id with a genctr for use-after-free validation")
>
> But they depend on this upstream commit to initialize the 'cmd' field in
> some cases:
>
> f4b9e6c90c57 ("nvme: use driver pdu command for passthrough")
>
> Does it sound like I'm on the right track? The 5.15LTS and later seems to be okay.
>
If you apply that commit, does it solve the issue for you?
thanks,
greg k-h
