From 93cce82700015ed8b02a4ab55dcf8563e50b13e2 Mon Sep 17 00:00:00 2001 From: chenguanyou Date: Mon, 11 Sep 2023 20:59:39 +0800 Subject: [PATCH] Fix "rd" command to display data on zram on Linux 5.17 and later Fix "rd" command to display data on zram on Linux 5.17 and later kernels that contain commits a41ec880aa7b ("zsmalloc: move huge compressed obj from page to zspage"), ffedd09fa9b0 ("zsmalloc: Stop using slab fields in struct page"), and on Linux 6.1 and later that contain commit f635725c3905 ("zram: do not waste zram_table_entry flags bits"). Also, fix a bug that sets the same "byte" by memset() instead to pages containing the same "unsigned long" elements. Before: crash> mod -s zram zram.ko MODULE NAME BASE SIZE OBJECT FILE ffffffde224db800 zram ffffffde224d2000 57344 zram.ko crash> mod -s zsmalloc zsmalloc.ko MODULE NAME BASE SIZE OBJECT FILE ffffffde224c5180 zsmalloc ffffffde224bf000 40960 zsmalloc.ko crash> rd 0x13d89fb0 rd: zspage magic incorrect: b0 After: crash> rd 0x13d89fb0 13d89fb0: c2b54f7170883b20 ;.pqO.. Signed-off-by: chenguanyou Signed-off-by: Kazuhito Hagio --- defs.h | 16 ++++++++++++-- diskdump.c | 61 +++++++++++++++++++++++++++++++++++++++++++++--------- 2 files changed, 65 insertions(+), 12 deletions(-) diff --git a/defs.h b/defs.h index 96a7a2a31471..122d3a969bf9 100644 --- a/defs.h +++ b/defs.h @@ -2225,6 +2225,7 @@ struct offset_table { /* stash of commonly-used offsets */ long module_memory_base; long module_memory_size; long irq_data_irq; + long zspage_huge; }; struct size_table { /* stash of commonly-used sizes */ @@ -7208,8 +7209,7 @@ ulong try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulon #define SECTOR_SHIFT 9 #define SECTORS_PER_PAGE_SHIFT (PAGESHIFT() - SECTOR_SHIFT) #define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT) -#define ZRAM_FLAG_SHIFT (1<<24) -#define ZRAM_FLAG_SAME_BIT (1<<25) + struct zspage { struct { unsigned int fullness : 2; @@ -7221,6 +7221,18 @@ struct zspage { unsigned int freeobj; }; +struct zspage_5_17 { + struct { + unsigned int huge : 1; + unsigned int fullness : 2; + unsigned int class : 9; + unsigned int isolated : 3; + unsigned int magic : 8; + }; + unsigned int inuse; + unsigned int freeobj; +}; + /* * makedumpfile.c */ diff --git a/diskdump.c b/diskdump.c index 2c284ff3f97f..dd7bd9f66fb5 100644 --- a/diskdump.c +++ b/diskdump.c @@ -2745,15 +2745,32 @@ diskdump_device_dump_info(FILE *ofp) } } +static long ZRAM_FLAG_SHIFT; +static long ZRAM_FLAG_SAME_BIT; + static void zram_init(void) { + long zram_lock; + MEMBER_OFFSET_INIT(zram_mempoll, "zram", "mem_pool"); MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor"); MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "flags"); if (INVALID_MEMBER(zram_table_flag)) MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "value"); STRUCT_SIZE_INIT(zram_table_entry, "zram_table_entry"); + MEMBER_OFFSET_INIT(zspoll_size_class, "zs_pool", "size_class"); + MEMBER_OFFSET_INIT(size_class_size, "size_class", "size"); + MEMBER_OFFSET_INIT(zspage_huge, "zspage", "huge"); + + if (enumerator_value("ZRAM_LOCK", &zram_lock)) + ZRAM_FLAG_SHIFT = 1 << zram_lock; + else if (THIS_KERNEL_VERSION >= LINUX(6,1,0)) + ZRAM_FLAG_SHIFT = 1 << (PAGESHIFT() + 1); + else + ZRAM_FLAG_SHIFT = 1 << 24; + + ZRAM_FLAG_SAME_BIT = ZRAM_FLAG_SHIFT << 1; } static unsigned char * @@ -2761,9 +2778,11 @@ zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf) { ulong obj, off, class, page, zspage; struct zspage zspage_s; + struct zspage_5_17 zspage_5_17_s; physaddr_t paddr; unsigned int obj_idx, class_idx, size; ulong pages[2], sizes[2]; + ulong zs_magic; readmem(handle, KVADDR, &obj, sizeof(void *), "zram entry", FAULT_ON_ERROR); obj >>= OBJ_TAG_BITS; @@ -2772,11 +2791,19 @@ zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf) readmem(page + OFFSET(page_private), KVADDR, &zspage, sizeof(void *), "page_private", FAULT_ON_ERROR); - readmem(zspage, KVADDR, &zspage_s, sizeof(struct zspage), "zspage", FAULT_ON_ERROR); - class_idx = zspage_s.class; - if (zspage_s.magic != ZSPAGE_MAGIC) - error(FATAL, "zspage magic incorrect: %x\n", zspage_s.magic); + if (VALID_MEMBER(zspage_huge)) { + readmem(zspage, KVADDR, &zspage_5_17_s, sizeof(struct zspage_5_17), "zspage_5_17", FAULT_ON_ERROR); + class_idx = zspage_5_17_s.class; + zs_magic = zspage_5_17_s.magic; + } else { + readmem(zspage, KVADDR, &zspage_s, sizeof(struct zspage), "zspage", FAULT_ON_ERROR); + class_idx = zspage_s.class; + zs_magic = zspage_s.magic; + } + + if (zs_magic != ZSPAGE_MAGIC) + error(FATAL, "zspage magic incorrect: %x\n", zs_magic); class = pool + OFFSET(zspoll_size_class); class += (class_idx * sizeof(void *)); @@ -2794,8 +2821,13 @@ zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf) } pages[0] = page; - readmem(page + OFFSET(page_freelist), KVADDR, &pages[1], - sizeof(void *), "page_freelist", FAULT_ON_ERROR); + if (VALID_MEMBER(page_freelist)) + readmem(page + OFFSET(page_freelist), KVADDR, &pages[1], + sizeof(void *), "page_freelist", FAULT_ON_ERROR); + else + readmem(page + OFFSET(page_index), KVADDR, &pages[1], + sizeof(void *), "page_index", FAULT_ON_ERROR); + sizes[0] = PAGESIZE() - off; sizes[1] = size - sizes[0]; if (!is_page_ptr(pages[0], &paddr)) { @@ -2812,9 +2844,13 @@ zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf) readmem(paddr, PHYSADDR, zram_buf + sizes[0], sizes[1], "zram buffer[1]", FAULT_ON_ERROR); out: - readmem(page, KVADDR, &obj, sizeof(void *), "page flags", FAULT_ON_ERROR); - if (!(obj & (1<<10))) { //PG_OwnerPriv1 flag - return (zram_buf + ZS_HANDLE_SIZE); + if (VALID_MEMBER(zspage_huge)) { + if (!zspage_5_17_s.huge) + return (zram_buf + ZS_HANDLE_SIZE); + } else { + readmem(page, KVADDR, &obj, sizeof(void *), "page flags", FAULT_ON_ERROR); + if (!(obj & (1<<10))) // PG_OwnerPriv1 flag + return (zram_buf + ZS_HANDLE_SIZE); } return zram_buf; @@ -2993,7 +3029,12 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong readmem(zram_table_entry + OFFSET(zram_table_flag), KVADDR, &flags, sizeof(void *), "zram_table_flag", FAULT_ON_ERROR); if (!entry || (flags & ZRAM_FLAG_SAME_BIT)) { - memset(buf, entry, len); + ulong *same_buf = (ulong *)GETBUF(PAGESIZE()); + for (int count = 0; count < PAGESIZE() / sizeof(ulong); count++) { + same_buf[count] = entry; + } + memcpy(buf, same_buf + off, len); + FREEBUF(same_buf); goto out; } size = flags & (ZRAM_FLAG_SHIFT -1); -- 2.31.1