Re: [Crash-utility] 答复: [External Mail]Re: [PATCH v4] Fix: move huge compressed obj from page to zspage

Hi Kazu Thank you for your advice. > Does this mean that the current "memset(buf, entry, len)" is a bug, > because entry is ulong, right? If so, I agree. Yes. Subject: [PATCH] Fix: "rd" command to read zram buf on Linux 5.17 and later Kernel commit a41ec880aa7b ("zsmalloc: move huge compressed obj from page to zspage"), which is contained in Linux 5.17 and later kernels. Use zspage_5_17 to be compatible with later versions. Kernel commit ffedd09fa9b06 ("zsmalloc: Stop using slab fields in struct page"), page->index and page->freelist are at the same offset in struct page. Kernel commit f635725c3905e ("zram: do not waste zram_table_entry flags bits"), which is contained in Linux 6.1 and later kernels. let ZRAM_FLAG_SHIFT follow ZRAM_LOCK. 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.. Link: https://lkml.kernel.org/r/20211115185909.3949505-6-minchan@kernel.org Link: https://lkml.kernel.org/r/20220912152744.527438-1-senozhatsky@chromium.org Signed-off-by: chenguanyou <chenguanyou(a)xiaomi.com&gt; --- defs.h | 26 +++++++++++++++++++++ diskdump.c | 66 ++++++++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 80 insertions(+), 12 deletions(-) diff --git a/defs.h b/defs.h index 96a7a2a..2038351 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 */ @@ -7210,6 +7211,19 @@ ulong try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulon #define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT) #define ZRAM_FLAG_SHIFT (1<<24) #define ZRAM_FLAG_SAME_BIT (1<<25) + +struct zram_pageflags { + long ZRAM_LOCK; + long ZRAM_SAME; +}; + +/* + * diskdump.c + */ +extern struct zram_pageflags zram_pageflags; +#define ZRAM_PAGEFLAG_INIT(X, Y) (zram_pageflags.X = Y) +#define ZRAM_PAGEFLAG_VALUE(X) (zram_pageflags.X)

+ struct zspage { struct { unsigned int fullness : 2; @@ -7221,6 +7235,18 @@ 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 2c284ff..d6c114d 100644 --- a/diskdump.c +++ b/diskdump.c @@ -2745,6 +2745,8 @@ diskdump_device_dump_info(FILE *ofp) } } +struct zram_pageflags zram_pageflags = { 0 }; + static void zram_init(void) { @@ -2754,6 +2756,17 @@ zram_init(void) 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 (!ZRAM_PAGEFLAG_VALUE(ZRAM_LOCK)) { + ZRAM_PAGEFLAG_INIT(ZRAM_LOCK, 24); + if (!enumerator_value("ZRAM_LOCK", &zram_pageflags.ZRAM_LOCK) + && THIS_KERNEL_VERSION >= LINUX(6,1,0)) + ZRAM_PAGEFLAG_INIT(ZRAM_LOCK, PAGESHIFT() + 1); + ZRAM_PAGEFLAG_INIT(ZRAM_SAME, ZRAM_PAGEFLAG_VALUE(ZRAM_LOCK) + 1); + } } static unsigned char * @@ -2761,9 +2774,11 @@ 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 +2787,19 @@ 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 +2817,13 @@ 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 +2840,15 @@ 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)) { + readmem(page, KVADDR, &obj, sizeof(void *), "page flags", FAULT_ON_ERROR); + if (!(obj & (1<<10))) { //PG_OwnerPriv1 flag + return (zram_buf + ZS_HANDLE_SIZE); + } + } else { + if (!zspage_5_17_s.huge) { + return (zram_buf + ZS_HANDLE_SIZE); + } } return zram_buf; @@ -2929,6 +2963,7 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong unsigned char *outbuf = NULL; ulong zram, zram_table_entry, sector, index, entry, flags, size, outsize, off; + unsigned long *same_buf = NULL; if (INVALID_MEMBER(zram_compressor)) { zram_init(); @@ -2992,11 +3027,18 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong sizeof(void *), "entry of table", FAULT_ON_ERROR); 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); + + if (!entry || flags & (1 << ZRAM_PAGEFLAG_VALUE(ZRAM_SAME))) { + same_buf = (unsigned long *)GETBUF(PAGESIZE()); + for (int count = 0; count < PAGESIZE() / sizeof(unsigned long); count++) { + same_buf[count] = entry; + } + memcpy(buf, same_buf + off, len); + FREEBUF(same_buf); goto out; } - size = flags & (ZRAM_FLAG_SHIFT -1); + + size = flags & ((1 << ZRAM_PAGEFLAG_VALUE(ZRAM_LOCK)) - 1); if (size == 0) { len = 0; goto out; -- 2.39.0 Thanks. Guanyou. -- Crash-utility mailing list Crash-utility(a)redhat.com https://listman.redhat.com/mailman/listinfo/crash-utility Contribution Guidelines: https://github.com/crash-utility/crash/wiki