On Tue, 16 Nov 2021, Jan Beulich wrote:
On 15.11.2021 23:27, Stefano Stabellini wrote:
From: Stefano Stabellini stefano.stabellini@xilinx.com
In case of errors in xenbus_init (e.g. missing xen_store_gfn parameter), we goto out_error but we forget to reset xen_store_domain_type to XS_UNKNOWN. As a consequence xenbus_probe_initcall and other initcalls will still try to initialize xenstore resulting into a crash at boot.
[ 2.479830] Call trace: [ 2.482314] xb_init_comms+0x18/0x150 [ 2.486354] xs_init+0x34/0x138 [ 2.489786] xenbus_probe+0x4c/0x70 [ 2.498432] xenbus_probe_initcall+0x2c/0x7c [ 2.503944] do_one_initcall+0x54/0x1b8 [ 2.507358] kernel_init_freeable+0x1ac/0x210 [ 2.511617] kernel_init+0x28/0x130 [ 2.516112] ret_from_fork+0x10/0x20
Cc: Stable@vger.kernel.org Cc: jbeulich@suse.com Signed-off-by: Stefano Stabellini stefano.stabellini@xilinx.com
For the immediate purpose as described this looks okay, so Reviewed-by: Jan Beulich jbeulich@suse.com
Thank you!
However, aren't there further pieces missing on this error patch:
- clearing of xenstored_ready in case it got set,
- rolling back xenstored_local_init() (XS_LOCAL) and xen_remap() (XS_HVM).
And shouldn't xs_init() failure when called from xenbus_probe() also result in the driver not giving the appearance of being usable?
I prioritized this patch because I have a direct test case for this issue and I can see that this patch solves it. But what you wrote is true, and I can have a look in the following weeks.
--- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -909,7 +909,7 @@ static struct notifier_block xenbus_resume_nb = { static int __init xenbus_init(void) {
- int err = 0;
- int err; uint64_t v = 0; xen_store_domain_type = XS_UNKNOWN;
Minor remark: You may want to take the opportunity and add the missing blank line here to visually separate the assignment from the declarations.
Jan