The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 133e049a3f8c91b175029fb6a59b6039d5e79cba Gitweb: https://git.kernel.org/tip/133e049a3f8c91b175029fb6a59b6039d5e79cba Author: Jarkko Sakkinen jarkko@kernel.org AuthorDate: Tue, 06 Sep 2022 03:02:20 +03:00 Committer: Dave Hansen dave.hansen@linux.intel.com CommitterDate: Thu, 08 Sep 2022 13:27:44 -07:00
x86/sgx: Do not fail on incomplete sanitization on premature stop of ksgxd
Unsanitized pages trigger WARN_ON() unconditionally, which can panic the whole computer, if /proc/sys/kernel/panic_on_warn is set.
In sgx_init(), if misc_register() fails or misc_register() succeeds but neither sgx_drv_init() nor sgx_vepc_init() succeeds, then ksgxd will be prematurely stopped. This may leave unsanitized pages, which will result a false warning.
Refine __sgx_sanitize_pages() to return:
1. Zero when the sanitization process is complete or ksgxd has been requested to stop. 2. The number of unsanitized pages otherwise.
Fixes: 51ab30eb2ad4 ("x86/sgx: Replace section->init_laundry_list with sgx_dirty_page_list") Reported-by: Paul Menzel pmenzel@molgen.mpg.de Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Reinette Chatre reinette.chatre@intel.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-sgx/20220825051827.246698-1-jarkko@kernel.org/... Link: https://lkml.kernel.org/r/20220906000221.34286-2-jarkko@kernel.org --- arch/x86/kernel/cpu/sgx/main.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 515e2a5..0aad028 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -49,9 +49,13 @@ static LIST_HEAD(sgx_dirty_page_list); * Reset post-kexec EPC pages to the uninitialized state. The pages are removed * from the input list, and made available for the page allocator. SECS pages * prepending their children in the input list are left intact. + * + * Return 0 when sanitization was successful or kthread was stopped, and the + * number of unsanitized pages otherwise. */ -static void __sgx_sanitize_pages(struct list_head *dirty_page_list) +static unsigned long __sgx_sanitize_pages(struct list_head *dirty_page_list) { + unsigned long left_dirty = 0; struct sgx_epc_page *page; LIST_HEAD(dirty); int ret; @@ -59,7 +63,7 @@ static void __sgx_sanitize_pages(struct list_head *dirty_page_list) /* dirty_page_list is thread-local, no need for a lock: */ while (!list_empty(dirty_page_list)) { if (kthread_should_stop()) - return; + return 0;
page = list_first_entry(dirty_page_list, struct sgx_epc_page, list);
@@ -92,12 +96,14 @@ static void __sgx_sanitize_pages(struct list_head *dirty_page_list) } else { /* The page is not yet clean - move to the dirty list. */ list_move_tail(&page->list, &dirty); + left_dirty++; }
cond_resched(); }
list_splice(&dirty, dirty_page_list); + return left_dirty; }
static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page) @@ -395,10 +401,7 @@ static int ksgxd(void *p) * required for SECS pages, whose child pages blocked EREMOVE. */ __sgx_sanitize_pages(&sgx_dirty_page_list); - __sgx_sanitize_pages(&sgx_dirty_page_list); - - /* sanity check: */ - WARN_ON(!list_empty(&sgx_dirty_page_list)); + WARN_ON(__sgx_sanitize_pages(&sgx_dirty_page_list));
while (!kthread_should_stop()) { if (try_to_freeze())