From 4a8ef190c16f724a0bc23ef71bda44b8aef4afaa Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Fri, 19 Mar 2021 18:12:44 +0800 Subject: [PATCH 1/3] mm, slub: use pGp to print page flags As pGp has been already introduced in printk, we'd better use it to make the output human readable. Before this change, the output is, [ 6155.716018] INFO: Slab 0x000000004027dd4f objects=33 used=3 fp=0x000000008cd1579c flags=0x17ffffc0010200 While after this change, the output is, [ 8846.517809] INFO: Slab 0x00000000f42a2c60 objects=33 used=3 fp=0x0000000060d32ca8 flags=0x17ffffc0010200(slab|head) Signed-off-by: Yafang Shao Reviewed-by: David Hildenbrand Reviewed-by: Vlastimil Babka Acked-by: David Rientjes Acked-by: Christoph Lameter Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Miaohe Lin Reviewed-by: Andy Shevchenko Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210319101246.73513-2-laoar.shao@gmail.com --- mm/slub.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index f5baf429654f..91eea1930cc1 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -641,8 +641,9 @@ void print_tracking(struct kmem_cache *s, void *object) static void print_page_info(struct page *page) { - pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n", - page, page->objects, page->inuse, page->freelist, page->flags); + pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=%#lx(%pGp)\n", + page, page->objects, page->inuse, page->freelist, + page->flags, &page->flags); } From 96b94abc12e6ec648f770776522de20c073c6eca Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Fri, 19 Mar 2021 18:12:45 +0800 Subject: [PATCH 2/3] mm, slub: don't combine pr_err with INFO It is strange to combine "pr_err" with "INFO", so let's remove the prefix completely. This patch is motivated by David's comment[1]. - before the patch [ 8846.517809] INFO: Slab 0x00000000f42a2c60 objects=33 used=3 fp=0x0000000060d32ca8 flags=0x17ffffc0010200(slab|head) - after the patch [ 6343.396602] Slab 0x000000004382e02b objects=33 used=3 fp=0x000000009ae06ffc flags=0x17ffffc0010200(slab|head) [1] https://lore.kernel.org/linux-mm/b9c0f2b6-e9b0-0c36-ebdd-2bc684c5a762@redhat.com/#t Suggested-by: Vlastimil Babka Signed-off-by: Yafang Shao Acked-by: Vlastimil Babka Reviewed-by: Miaohe Lin Reviewed-by: Andy Shevchenko Reviewed-by: David Hildenbrand Acked-by: David Rientjes Cc: Matthew Wilcox Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210319101246.73513-3-laoar.shao@gmail.com --- mm/slub.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 91eea1930cc1..5eb120fdde8b 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -615,7 +615,7 @@ static void print_track(const char *s, struct track *t, unsigned long pr_time) if (!t->addr) return; - pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n", + pr_err("%s in %pS age=%lu cpu=%u pid=%d\n", s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid); #ifdef CONFIG_STACKTRACE { @@ -641,7 +641,7 @@ void print_tracking(struct kmem_cache *s, void *object) static void print_page_info(struct page *page) { - pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=%#lx(%pGp)\n", + pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%#lx(%pGp)\n", page, page->objects, page->inuse, page->freelist, page->flags, &page->flags); @@ -698,7 +698,7 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) print_page_info(page); - pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n", + pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n", p, p - addr, get_freepointer(s, p)); if (s->flags & SLAB_RED_ZONE) @@ -791,7 +791,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page, end--; slab_bug(s, "%s overwritten", what); - pr_err("INFO: 0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n", + pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n", fault, end - 1, fault - addr, fault[0], value); print_trailer(s, page, object); @@ -3869,7 +3869,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page, for_each_object(p, s, addr, page->objects) { if (!test_bit(__obj_to_index(s, addr, p), map)) { - pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr); + pr_err("Object 0x%p @offset=%tu\n", p, p - addr); print_tracking(s, p); } } From c244297acbe51f1db5764966c02cdbd69927f218 Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Fri, 19 Mar 2021 18:12:46 +0800 Subject: [PATCH 3/3] vsprintf: dump full information of page flags in pGp Currently the pGp only shows the names of page flags, rather than the full information including section, node, zone, last cpupid and kasan tag. While it is not easy to parse these information manually because there're so many flavors. Let's interpret them in pGp as well. To be compitable with the existed format of pGp, the new introduced ones also use '|' as the separator, then the user tools parsing pGp won't need to make change, suggested by Matthew. The new information is tracked onto the end of the existed one. On example of the output in mm/slub.c as follows, - Before the patch, [ 6343.396602] Slab 0x000000004382e02b objects=33 used=3 fp=0x000000009ae06ffc flags=0x17ffffc0010200(slab|head) - After the patch, [ 8448.272530] Slab 0x0000000090797883 objects=33 used=3 fp=0x00000000790f1c26 flags=0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) The documentation and test cases are also updated. The output of the test cases as follows, [68599.816764] test_printf: loaded. [68599.819068] test_printf: all 388 tests passed [68599.830367] test_printf: unloaded. [lkp@intel.com: reported issues in the prev version in test_printf.c] Signed-off-by: Yafang Shao Cc: David Hildenbrand Cc: Joe Perches Cc: Miaohe Lin Cc: Vlastimil Babka Cc: Andy Shevchenko Cc: Matthew Wilcox Cc: Petr Mladek Cc: kernel test robot Reviewed-by: Sergey Senozhatsky Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210319101246.73513-4-laoar.shao@gmail.com --- Documentation/core-api/printk-formats.rst | 2 +- lib/test_printf.c | 90 ++++++++++++++++++++--- lib/vsprintf.c | 66 +++++++++++++++-- 3 files changed, 142 insertions(+), 16 deletions(-) diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 160e710d992f..00d07c7eefd4 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -540,7 +540,7 @@ Flags bitfields such as page flags, gfp_flags :: - %pGp referenced|uptodate|lru|active|private + %pGp referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff %pGg GFP_USER|GFP_DMA32|GFP_NOWARN %pGv read|exec|mayread|maywrite|mayexec|denywrite diff --git a/lib/test_printf.c b/lib/test_printf.c index 95a2f82427c7..27b964ec723d 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -577,24 +577,98 @@ netdev_features(void) { } +struct page_flags_test { + int width; + int shift; + int mask; + unsigned long value; + const char *fmt; + const char *name; +}; + +static struct page_flags_test pft[] = { + {SECTIONS_WIDTH, SECTIONS_PGSHIFT, SECTIONS_MASK, + 0, "%d", "section"}, + {NODES_WIDTH, NODES_PGSHIFT, NODES_MASK, + 0, "%d", "node"}, + {ZONES_WIDTH, ZONES_PGSHIFT, ZONES_MASK, + 0, "%d", "zone"}, + {LAST_CPUPID_WIDTH, LAST_CPUPID_PGSHIFT, LAST_CPUPID_MASK, + 0, "%#x", "lastcpupid"}, + {KASAN_TAG_WIDTH, KASAN_TAG_PGSHIFT, KASAN_TAG_MASK, + 0, "%#x", "kasantag"}, +}; + +static void __init +page_flags_test(int section, int node, int zone, int last_cpupid, + int kasan_tag, int flags, const char *name, char *cmp_buf) +{ + unsigned long values[] = {section, node, zone, last_cpupid, kasan_tag}; + unsigned long page_flags = 0; + unsigned long size = 0; + bool append = false; + int i; + + flags &= BIT(NR_PAGEFLAGS) - 1; + if (flags) { + page_flags |= flags; + snprintf(cmp_buf + size, BUF_SIZE - size, "%s", name); + size = strlen(cmp_buf); +#if SECTIONS_WIDTH || NODES_WIDTH || ZONES_WIDTH || \ + LAST_CPUPID_WIDTH || KASAN_TAG_WIDTH + /* Other information also included in page flags */ + snprintf(cmp_buf + size, BUF_SIZE - size, "|"); + size = strlen(cmp_buf); +#endif + } + + /* Set the test value */ + for (i = 0; i < ARRAY_SIZE(pft); i++) + pft[i].value = values[i]; + + for (i = 0; i < ARRAY_SIZE(pft); i++) { + if (!pft[i].width) + continue; + + if (append) { + snprintf(cmp_buf + size, BUF_SIZE - size, "|"); + size = strlen(cmp_buf); + } + + page_flags |= (pft[i].value & pft[i].mask) << pft[i].shift; + snprintf(cmp_buf + size, BUF_SIZE - size, "%s=", pft[i].name); + size = strlen(cmp_buf); + snprintf(cmp_buf + size, BUF_SIZE - size, pft[i].fmt, + pft[i].value & pft[i].mask); + size = strlen(cmp_buf); + append = true; + } + + test(cmp_buf, "%pGp", &page_flags); +} + static void __init flags(void) { unsigned long flags; - gfp_t gfp; char *cmp_buffer; + gfp_t gfp; + + cmp_buffer = kmalloc(BUF_SIZE, GFP_KERNEL); + if (!cmp_buffer) + return; flags = 0; - test("", "%pGp", &flags); + page_flags_test(0, 0, 0, 0, 0, flags, "", cmp_buffer); - /* Page flags should filter the zone id */ flags = 1UL << NR_PAGEFLAGS; - test("", "%pGp", &flags); + page_flags_test(0, 0, 0, 0, 0, flags, "", cmp_buffer); flags |= 1UL << PG_uptodate | 1UL << PG_dirty | 1UL << PG_lru | 1UL << PG_active | 1UL << PG_swapbacked; - test("uptodate|dirty|lru|active|swapbacked", "%pGp", &flags); - + page_flags_test(1, 1, 1, 0x1fffff, 1, flags, + "uptodate|dirty|lru|active|swapbacked", + cmp_buffer); flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC | VM_DENYWRITE; @@ -609,10 +683,6 @@ flags(void) gfp = __GFP_ATOMIC; test("__GFP_ATOMIC", "%pGg", &gfp); - cmp_buffer = kmalloc(BUF_SIZE, GFP_KERNEL); - if (!cmp_buffer) - return; - /* Any flags not translated by the table should remain numeric */ gfp = ~__GFP_BITS_MASK; snprintf(cmp_buffer, BUF_SIZE, "%#lx", (unsigned long) gfp); diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 41ddc353ebb8..92e6085eef15 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1916,6 +1916,66 @@ char *format_flags(char *buf, char *end, unsigned long flags, return buf; } +struct page_flags_fields { + int width; + int shift; + int mask; + const struct printf_spec *spec; + const char *name; +}; + +static const struct page_flags_fields pff[] = { + {SECTIONS_WIDTH, SECTIONS_PGSHIFT, SECTIONS_MASK, + &default_dec_spec, "section"}, + {NODES_WIDTH, NODES_PGSHIFT, NODES_MASK, + &default_dec_spec, "node"}, + {ZONES_WIDTH, ZONES_PGSHIFT, ZONES_MASK, + &default_dec_spec, "zone"}, + {LAST_CPUPID_WIDTH, LAST_CPUPID_PGSHIFT, LAST_CPUPID_MASK, + &default_flag_spec, "lastcpupid"}, + {KASAN_TAG_WIDTH, KASAN_TAG_PGSHIFT, KASAN_TAG_MASK, + &default_flag_spec, "kasantag"}, +}; + +static +char *format_page_flags(char *buf, char *end, unsigned long flags) +{ + unsigned long main_flags = flags & (BIT(NR_PAGEFLAGS) - 1); + bool append = false; + int i; + + /* Page flags from the main area. */ + if (main_flags) { + buf = format_flags(buf, end, main_flags, pageflag_names); + append = true; + } + + /* Page flags from the fields area */ + for (i = 0; i < ARRAY_SIZE(pff); i++) { + /* Skip undefined fields. */ + if (!pff[i].width) + continue; + + /* Format: Flag Name + '=' (equals sign) + Number + '|' (separator) */ + if (append) { + if (buf < end) + *buf = '|'; + buf++; + } + + buf = string(buf, end, pff[i].name, default_str_spec); + if (buf < end) + *buf = '='; + buf++; + buf = number(buf, end, (flags >> pff[i].shift) & pff[i].mask, + *pff[i].spec); + + append = true; + } + + return buf; +} + static noinline_for_stack char *flags_string(char *buf, char *end, void *flags_ptr, struct printf_spec spec, const char *fmt) @@ -1928,11 +1988,7 @@ char *flags_string(char *buf, char *end, void *flags_ptr, switch (fmt[1]) { case 'p': - flags = *(unsigned long *)flags_ptr; - /* Remove zone id */ - flags &= (1UL << NR_PAGEFLAGS) - 1; - names = pageflag_names; - break; + return format_page_flags(buf, end, *(unsigned long *)flags_ptr); case 'v': flags = *(unsigned long *)flags_ptr; names = vmaflag_names;