From 582f0f3864110e1c6e4af3af768e1c2453ba2306 Mon Sep 17 00:00:00 2001 From: Pasha Tatashin Date: Tue, 23 Dec 2025 09:01:40 -0500 Subject: kho: validate preserved memory map during population If the previous kernel enabled KHO but did not call kho_finalize() (e.g., CONFIG_LIVEUPDATE=n or userspace skipped the finalization step), the 'preserved-memory-map' property in the FDT remains empty/zero. Previously, kho_populate() would succeed regardless of the memory map's state, reserving the incoming scratch regions in memblock. However, kho_memory_init() would later fail to deserialize the empty map. By that time, the scratch regions were already registered, leading to partial initialization and subsequent list corruption (freeing scratch area twice) during kho_init(). Move the validation of the preserved memory map earlier into kho_populate(). If the memory map is empty/NULL: 1. Abort kho_populate() immediately with -ENOENT. 2. Do not register or reserve the incoming scratch memory, allowing the new kernel to reclaim those pages as standard free memory. 3. Leave the global 'kho_in' state uninitialized. Consequently, kho_memory_init() sees no active KHO context (kho_in.mem_chunks_phys is 0) and falls back to kho_reserve_scratch(), allocating fresh scratch memory as if it were a standard cold boot. Link: https://lkml.kernel.org/r/20251223140140.2090337-1-pasha.tatashin@soleen.com Fixes: de51999e687c ("kho: allow memory preservation state updates after finalization") Signed-off-by: Pasha Tatashin Reported-by: Ricardo Neri Closes: https://lore.kernel.org/all/20251218215613.GA17304@ranerica-svr.sc.intel.com Reviewed-by: Mike Rapoport (Microsoft) Tested-by: Ricardo Neri Reviewed-by: Pratyush Yadav Cc: Alexander Graf Signed-off-by: Andrew Morton --- kernel/liveupdate/kexec_handover.c | 37 +++++++++++++++++++------------------ 1 file changed, 19 insertions(+), 18 deletions(-) (limited to 'kernel') diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 9dc51fab604f..d4482b6e3cae 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -460,27 +460,23 @@ static void __init deserialize_bitmap(unsigned int order, } } -/* Return true if memory was deserizlied */ -static bool __init kho_mem_deserialize(const void *fdt) +/* Returns physical address of the preserved memory map from FDT */ +static phys_addr_t __init kho_get_mem_map_phys(const void *fdt) { - struct khoser_mem_chunk *chunk; const void *mem_ptr; - u64 mem; int len; mem_ptr = fdt_getprop(fdt, 0, PROP_PRESERVED_MEMORY_MAP, &len); if (!mem_ptr || len != sizeof(u64)) { pr_err("failed to get preserved memory bitmaps\n"); - return false; + return 0; } - mem = get_unaligned((const u64 *)mem_ptr); - chunk = mem ? phys_to_virt(mem) : NULL; - - /* No preserved physical pages were passed, no deserialization */ - if (!chunk) - return false; + return get_unaligned((const u64 *)mem_ptr); +} +static void __init kho_mem_deserialize(struct khoser_mem_chunk *chunk) +{ while (chunk) { unsigned int i; @@ -489,8 +485,6 @@ static bool __init kho_mem_deserialize(const void *fdt) &chunk->bitmaps[i]); chunk = KHOSER_LOAD_PTR(chunk->hdr.next); } - - return true; } /* @@ -1253,6 +1247,7 @@ bool kho_finalized(void) struct kho_in { phys_addr_t fdt_phys; phys_addr_t scratch_phys; + phys_addr_t mem_map_phys; struct kho_debugfs dbg; }; @@ -1434,12 +1429,10 @@ static void __init kho_release_scratch(void) void __init kho_memory_init(void) { - if (kho_in.scratch_phys) { + if (kho_in.mem_map_phys) { kho_scratch = phys_to_virt(kho_in.scratch_phys); kho_release_scratch(); - - if (!kho_mem_deserialize(kho_get_fdt())) - kho_in.fdt_phys = 0; + kho_mem_deserialize(phys_to_virt(kho_in.mem_map_phys)); } else { kho_reserve_scratch(); } @@ -1448,8 +1441,9 @@ void __init kho_memory_init(void) void __init kho_populate(phys_addr_t fdt_phys, u64 fdt_len, phys_addr_t scratch_phys, u64 scratch_len) { - void *fdt = NULL; struct kho_scratch *scratch = NULL; + phys_addr_t mem_map_phys; + void *fdt = NULL; int err = 0; unsigned int scratch_cnt = scratch_len / sizeof(*kho_scratch); @@ -1475,6 +1469,12 @@ void __init kho_populate(phys_addr_t fdt_phys, u64 fdt_len, goto out; } + mem_map_phys = kho_get_mem_map_phys(fdt); + if (!mem_map_phys) { + err = -ENOENT; + goto out; + } + scratch = early_memremap(scratch_phys, scratch_len); if (!scratch) { pr_warn("setup: failed to memremap scratch (phys=0x%llx, len=%lld)\n", @@ -1515,6 +1515,7 @@ void __init kho_populate(phys_addr_t fdt_phys, u64 fdt_len, kho_in.fdt_phys = fdt_phys; kho_in.scratch_phys = scratch_phys; + kho_in.mem_map_phys = mem_map_phys; kho_scratch_cnt = scratch_cnt; pr_info("found kexec handover data.\n"); -- cgit v1.2.3 From e561383a39ed6e5c85a0b2369720743b694327ae Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Wed, 31 Dec 2025 16:03:09 +0800 Subject: powerpc/watchdog: add support for hardlockup_sys_info sysctl Commit a9af76a78760 ("watchdog: add sys_info sysctls to dump sys info on system lockup") adds 'hardlock_sys_info' systcl knob for general kernel watchdog to control what kinds of system debug info to be dumped on hardlockup. Add similar support in powerpc watchdog code to make the sysctl knob more general, which also fixes a compiling warning in general watchdog code reported by 0day bot. Link: https://lkml.kernel.org/r/20251231080309.39642-1-feng.tang@linux.alibaba.com Fixes: a9af76a78760 ("watchdog: add sys_info sysctls to dump sys info on system lockup") Signed-off-by: Feng Tang Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202512030920.NFKtekA7-lkp@intel.com/ Suggested-by: Petr Mladek Reviewed-by: Petr Mladek Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Nicholas Piggin Signed-off-by: Andrew Morton --- kernel/watchdog.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 0685e3a8aa0a..366122f4a0f8 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -71,7 +71,7 @@ unsigned int __read_mostly hardlockup_panic = * hard lockup is detected, it could be task, memory, lock etc. * Refer include/linux/sys_info.h for detailed bit definition. */ -static unsigned long hardlockup_si_mask; +unsigned long hardlockup_si_mask; #ifdef CONFIG_SYSFS -- cgit v1.2.3