From: Roger Pau Monné Date: Tue, 21 May 2024 09:55:09 +0000 (+0200) Subject: altcall: fix __alt_call_maybe_initdata so it's safe for livepatch X-Git-Tag: RELEASE-4.17.5~62 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=8d1c36d25a777bed97a8b5da0128fa7b9320f911;p=xen.git altcall: fix __alt_call_maybe_initdata so it's safe for livepatch 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 Reviewed-by: Andrew Cooper master commit: af4cd0a6a61cdb03bc1afca9478b05b0c9703599 master date: 2024-04-11 18:51:36 +0100 --- diff --git a/xen/include/xen/alternative-call.h b/xen/include/xen/alternative-call.h index 5c6b9a562b..10f7d7637e 100644 --- a/xen/include/xen/alternative-call.h +++ b/xen/include/xen/alternative-call.h @@ -50,7 +50,12 @@ #include -#define __alt_call_maybe_initdata __initdata +#ifdef CONFIG_LIVEPATCH +/* Must keep for livepatches to resolve alternative calls. */ +# define __alt_call_maybe_initdata __ro_after_init +#else +# define __alt_call_maybe_initdata __initdata +#endif #else