Re: [PATCH 2/4] device-tree: Remove __init from unflatten_dt_alloc()

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 19 Sep 2024, Michal Orzel wrote:
> With CONFIG_OVERLAY_DTB=y, unflatten_dt_alloc() is used as part of
> unflatten_dt_node() used during runtime. In case of a binary compiled
> such as unflatten_dt_alloc() does not get inlined (e.g. using -Og),
> attempt to add an overlay to Xen (xl dt-overlay add) results in a crash.
> 
> (XEN) Instruction Abort Trap. Syndrome=0x7
> (XEN) Walking Hypervisor VA 0xa00002c8cc0 on CPU2 via TTBR 0x0000000040340000
> (XEN) 0TH[0x014] = 0x4033ff7f
> (XEN) 1ST[0x000] = 0x4033ef7f
> (XEN) 2ND[0x001] = 0x4000004033af7f
> (XEN) 3RD[0x0c8] = 0x0
> (XEN) CPU2: Unexpected Trap: Instruction Abort
> (XEN) ----[ Xen-4.20-unstable  arm64  debug=y  Not tainted ]----
> ...
> (XEN) Xen call trace:
> (XEN)    [<00000a00002c8cc0>] 00000a00002c8cc0 (PC)
> (XEN)    [<00000a0000202410>] device-tree.c#unflatten_dt_node+0xd0/0x504 (LR)
> (XEN)    [<00000a0000204484>] unflatten_device_tree+0x54/0x1a0
> (XEN)    [<00000a000020800c>] 
> dt-overlay.c#handle_add_overlay_nodes+0x290/0x3d4
> (XEN)    [<00000a0000208360>] dt_overlay_sysctl+0x8c/0x110
> (XEN)    [<00000a000027714c>] arch_do_sysctl+0x1c/0x2c
> 
> Fixes: 9e9d2c079dc4 ("xen/arm/device: Remove __init from function type")
> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>  xen/common/device-tree/device-tree.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/common/device-tree/device-tree.c 
> b/xen/common/device-tree/device-tree.c
> index 8d1017a49d80..d0528c582565 100644
> --- a/xen/common/device-tree/device-tree.c
> +++ b/xen/common/device-tree/device-tree.c
> @@ -120,8 +120,8 @@ void dt_child_set_range(__be32 **cellp, int addrcells, 
> int sizecells,
>      dt_set_cell(cellp, sizecells, size);
>  }
>  
> -static void __init *unflatten_dt_alloc(unsigned long *mem, unsigned long 
> size,
> -                                       unsigned long align)
> +static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
> +                                unsigned long align)
>  {
>      void *res;
>  
> -- 
> 2.37.6
>