| Message ID | 20240411155314.73811-1-roger.pau@citrix.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | altcall: fix __alt_call_maybe_initdata so it's safe for livepatch | expand |
diff --git a/xen/include/xen/alternative-call.h b/xen/include/xen/alternative-call.h index 5c6b9a562b92..1896063e5da5 100644 --- a/xen/include/xen/alternative-call.h +++ b/xen/include/xen/alternative-call.h @@ -50,7 +50,12 @@ #include <asm/alternative.h> -#define __alt_call_maybe_initdata __initdata +#ifndef CONFIG_LIVEPATCH +# define __alt_call_maybe_initdata __initdata +#else +/* Must keep for livepatches to resolve alternative calls against them. */ +# define __alt_call_maybe_initdata __ro_after_init +#endif #else
Setting alternative call variables as __init is not safe for use with livepatch, as livepatches can rightfully introduce new alternative calls to structures marked as __alt_call_maybe_initdata (possibly just indirectly due to replacing existing functions that use those). Attempting to resolve those alternative calls then results in page faults as the variable that holds the function pointer address has been freed. When livepatch is supported use the __ro_after_init attribute instead of __initdata for __alt_call_maybe_initdata. Fixes: f26bb285949b ('xen: Implement xen/alternative-call.h for use in common code') Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- xen/include/xen/alternative-call.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)