From 654de1f9fd289e10a3de1daf0806051f05f57d92 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Wed, 25 Mar 2015 10:13:33 +0100 Subject: [PATCH] s390/hibernate: fix save and restore of kernel text section commit d74419495633493c9cd3f2bbeb7f3529d0edded6 upstream. Sebastian reported a crash caused by a jump label mismatch after resume. This happens because we do not save the kernel text section during suspend and therefore also do not restore it during resume, but use the kernel image that restores the old system. This means that after a suspend/resume cycle we lost all modifications done to the kernel text section. The reason for this is the pfn_is_nosave() function, which incorrectly returns that read-only pages don't need to be saved. This is incorrect since we mark the kernel text section read-only. We still need to make sure to not save and restore pages contained within NSS and DCSS segment. To fix this add an extra case for the kernel text section and only save those pages if they are not contained within an NSS segment. Fixes the following crash (and the above bugs as well): Jump label code mismatch at netif_receive_skb_internal+0x28/0xd0 Found: c0 04 00 00 00 00 Expected: c0 f4 00 00 00 11 New: c0 04 00 00 00 00 Kernel panic - not syncing: Corrupted kernel text CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.19.0-01975-gb1b096e70f23 #4 Call Trace: [<0000000000113972>] show_stack+0x72/0xf0 [<000000000081f15e>] dump_stack+0x6e/0x90 [<000000000081c4e8>] panic+0x108/0x2b0 [<000000000081be64>] jump_label_bug.isra.2+0x104/0x108 [<0000000000112176>] __jump_label_transform+0x9e/0xd0 [<00000000001121e6>] __sm_arch_jump_label_transform+0x3e/0x50 [<00000000001d1136>] multi_cpu_stop+0x12e/0x170 [<00000000001d1472>] cpu_stopper_thread+0xb2/0x168 [<000000000015d2ac>] smpboot_thread_fn+0x134/0x1b0 [<0000000000158baa>] kthread+0x10a/0x110 [<0000000000824a86>] kernel_thread_starter+0x6/0xc Reported-and-tested-by: Sebastian Ott Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/suspend.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/s390/kernel/suspend.c b/arch/s390/kernel/suspend.c index 1c4c5accd220..d3236c9e226b 100644 --- a/arch/s390/kernel/suspend.c +++ b/arch/s390/kernel/suspend.c @@ -138,6 +138,8 @@ int pfn_is_nosave(unsigned long pfn) { unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin)); unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end)); + unsigned long eshared_pfn = PFN_DOWN(__pa(&_eshared)) - 1; + unsigned long stext_pfn = PFN_DOWN(__pa(&_stext)); /* Always save lowcore pages (LC protection might be enabled). */ if (pfn <= LC_PAGES) @@ -145,6 +147,8 @@ int pfn_is_nosave(unsigned long pfn) if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn) return 1; /* Skip memory holes and read-only pages (NSS, DCSS, ...). */ + if (pfn >= stext_pfn && pfn <= eshared_pfn) + return ipl_info.type == IPL_TYPE_NSS ? 1 : 0; if (tprot(PFN_PHYS(pfn))) return 1; return 0; -- 2.11.0