On 9/3/21 4:49 AM, Juergen Gross wrote:
> A Xen PV guest doesn't have a legacy RTC device, so reset the legacy
> RTC flag. Otherwise the following WARN splat will occur at boot:
>
> [ 1.333404] WARNING: CPU: 1 PID: 1 at /home/gross/linux/head/drivers/rtc/rtc-mc146818-lib.c:25 mc146818_get_time+0x1be/0x210
> [ 1.333404] Modules linked in:
> [ 1.333404] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 5.14.0-rc7-default+ #282
> [ 1.333404] RIP: e030:mc146818_get_time+0x1be/0x210
> [ 1.333404] Code: c0 64 01 c5 83 fd 45 89 6b 14 7f 06 83 c5 64 89 6b 14 41 83 ec 01 b8 02 00 00 00 44 89 63 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 <0f> 0b 48 c7 c7 30 0e ef 82 4c 89 e6 e8 71 2a 24 00 48 c7 c0 ff ff
> [ 1.333404] RSP: e02b:ffffc90040093df8 EFLAGS: 00010002
> [ 1.333404] RAX: 00000000000000ff RBX: ffffc90040093e34 RCX: 0000000000000000
> [ 1.333404] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000000000000000d
> [ 1.333404] RBP: ffffffff82ef0e30 R08: ffff888005013e60 R09: 0000000000000000
> [ 1.333404] R10: ffffffff82373e9b R11: 0000000000033080 R12: 0000000000000200
> [ 1.333404] R13: 0000000000000000 R14: 0000000000000002 R15: ffffffff82cdc6d4
> [ 1.333404] FS: 0000000000000000(0000) GS:ffff88807d440000(0000) knlGS:0000000000000000
> [ 1.333404] CS: 10000e030 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1.333404] CR2: 0000000000000000 CR3: 000000000260a000 CR4: 0000000000050660
> [ 1.333404] Call Trace:
> [ 1.333404] ? wakeup_sources_sysfs_init+0x30/0x30
> [ 1.333404] ? rdinit_setup+0x2b/0x2b
> [ 1.333404] early_resume_init+0x23/0xa4
> [ 1.333404] ? cn_proc_init+0x36/0x36
> [ 1.333404] do_one_initcall+0x3e/0x200
> [ 1.333404] kernel_init_freeable+0x232/0x28e
> [ 1.333404] ? rest_init+0xd0/0xd0
> [ 1.333404] kernel_init+0x16/0x120
> [ 1.333404] ret_from_fork+0x1f/0x30
>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Fixes: 211e5db19d15 ("rtc: mc146818: Detect and handle broken RTCs") ?
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
