From 0b6ec8c0a3708f0a54b75ee1200772ec5226ec49 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Wed, 27 Jan 2016 15:37:58 +0100 Subject: debugobjects: Allow bigger number of early boot objects On my bigger s390 systems I always get "Out of memory. ODEBUG disabled". Since the number of objects is needed at compile time, we can not change the size dynamically before the caches etc are available. Doubling the size seems to do the trick. Since it is init data it will be freed anyway, this should be ok. Signed-off-by: Christian Borntraeger Link: http://lkml.kernel.org/r/1453905478-13409-1-git-send-email-borntraeger@de.ibm.com Signed-off-by: Thomas Gleixner --- lib/debugobjects.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 547f7f923dbc..519b5a10fd70 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -21,7 +21,7 @@ #define ODEBUG_HASH_BITS 14 #define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS) -#define ODEBUG_POOL_SIZE 512 +#define ODEBUG_POOL_SIZE 1024 #define ODEBUG_POOL_MIN_LEVEL 256 #define ODEBUG_CHUNK_SHIFT PAGE_SHIFT -- cgit v1.2.3-71-gd317 From 72676bb53f33fd0ef3a1484fc1ecfd306dc6ff40 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 2 Feb 2016 16:57:18 -0800 Subject: lib/test-string_helpers.c: fix and improve string_get_size() tests Recently added commit 564b026fbd0d ("string_helpers: fix precision loss for some inputs") fixed precision issues for string_get_size() and broke tests. Fix and improve them: test both STRING_UNITS_2 and STRING_UNITS_10 at a time, better failure reporting, test small an huge values. Fixes: 564b026fbd0d28e9 ("string_helpers: fix precision loss for some inputs") Signed-off-by: Vitaly Kuznetsov Cc: Andy Shevchenko Cc: Rasmus Villemoes Cc: James Bottomley Cc: James Bottomley Cc: "James E.J. Bottomley" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/test-string_helpers.c | 67 ++++++++++++++++++++++++++++++++++------------- 1 file changed, 49 insertions(+), 18 deletions(-) (limited to 'lib') diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c index 98866a770770..25b5cbfb7615 100644 --- a/lib/test-string_helpers.c +++ b/lib/test-string_helpers.c @@ -327,36 +327,67 @@ out: } #define string_get_size_maxbuf 16 -#define test_string_get_size_one(size, blk_size, units, exp_result) \ +#define test_string_get_size_one(size, blk_size, exp_result10, exp_result2) \ do { \ - BUILD_BUG_ON(sizeof(exp_result) >= string_get_size_maxbuf); \ - __test_string_get_size((size), (blk_size), (units), \ - (exp_result)); \ + BUILD_BUG_ON(sizeof(exp_result10) >= string_get_size_maxbuf); \ + BUILD_BUG_ON(sizeof(exp_result2) >= string_get_size_maxbuf); \ + __test_string_get_size((size), (blk_size), (exp_result10), \ + (exp_result2)); \ } while (0) -static __init void __test_string_get_size(const u64 size, const u64 blk_size, - const enum string_size_units units, - const char *exp_result) +static __init void test_string_get_size_check(const char *units, + const char *exp, + char *res, + const u64 size, + const u64 blk_size) { - char buf[string_get_size_maxbuf]; - - string_get_size(size, blk_size, units, buf, sizeof(buf)); - if (!memcmp(buf, exp_result, strlen(exp_result) + 1)) + if (!memcmp(res, exp, strlen(exp) + 1)) return; - buf[sizeof(buf) - 1] = '\0'; - pr_warn("Test 'test_string_get_size_one' failed!\n"); - pr_warn("string_get_size(size = %llu, blk_size = %llu, units = %d\n", + res[string_get_size_maxbuf - 1] = '\0'; + + pr_warn("Test 'test_string_get_size' failed!\n"); + pr_warn("string_get_size(size = %llu, blk_size = %llu, units = %s)\n", size, blk_size, units); - pr_warn("expected: '%s', got '%s'\n", exp_result, buf); + pr_warn("expected: '%s', got '%s'\n", exp, res); +} + +static __init void __test_string_get_size(const u64 size, const u64 blk_size, + const char *exp_result10, + const char *exp_result2) +{ + char buf10[string_get_size_maxbuf]; + char buf2[string_get_size_maxbuf]; + + string_get_size(size, blk_size, STRING_UNITS_10, buf10, sizeof(buf10)); + string_get_size(size, blk_size, STRING_UNITS_2, buf2, sizeof(buf2)); + + test_string_get_size_check("STRING_UNITS_10", exp_result10, buf10, + size, blk_size); + + test_string_get_size_check("STRING_UNITS_2", exp_result2, buf2, + size, blk_size); } static __init void test_string_get_size(void) { - test_string_get_size_one(16384, 512, STRING_UNITS_2, "8.00 MiB"); - test_string_get_size_one(8192, 4096, STRING_UNITS_10, "32.7 MB"); - test_string_get_size_one(1, 512, STRING_UNITS_10, "512 B"); + /* small values */ + test_string_get_size_one(0, 512, "0 B", "0 B"); + test_string_get_size_one(1, 512, "512 B", "512 B"); + test_string_get_size_one(1100, 1, "1.10 kB", "1.07 KiB"); + + /* normal values */ + test_string_get_size_one(16384, 512, "8.39 MB", "8.00 MiB"); + test_string_get_size_one(500118192, 512, "256 GB", "238 GiB"); + test_string_get_size_one(8192, 4096, "33.6 MB", "32.0 MiB"); + + /* weird block sizes */ + test_string_get_size_one(3000, 1900, "5.70 MB", "5.44 MiB"); + + /* huge values */ + test_string_get_size_one(U64_MAX, 4096, "75.6 ZB", "64.0 ZiB"); + test_string_get_size_one(4096, U64_MAX, "75.6 ZB", "64.0 ZiB"); } static int __init test_string_helpers_init(void) -- cgit v1.2.3-71-gd317 From 46437f9a554fbe3e110580ca08ab703b59f2f95a Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 2 Feb 2016 16:57:52 -0800 Subject: radix-tree: fix race in gang lookup If the indirect_ptr bit is set on a slot, that indicates we need to redo the lookup. Introduce a new function radix_tree_iter_retry() which forces the loop to retry the lookup by setting 'slot' to NULL and turning the iterator back to point at the problematic entry. This is a pretty rare problem to hit at the moment; the lookup has to race with a grow of the radix tree from a height of 0. The consequences of hitting this race are that gang lookup could return a pointer to a radix_tree_node instead of a pointer to whatever the user had inserted in the tree. Fixes: cebbd29e1c2f ("radix-tree: rewrite gang lookup using iterator") Signed-off-by: Matthew Wilcox Cc: Hugh Dickins Cc: Ohad Ben-Cohen Cc: Konstantin Khlebnikov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/radix-tree.h | 16 ++++++++++++++++ lib/radix-tree.c | 12 ++++++++++-- 2 files changed, 26 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 7c88ad156a29..00b17c526c1f 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -378,6 +378,22 @@ radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) void **radix_tree_next_chunk(struct radix_tree_root *root, struct radix_tree_iter *iter, unsigned flags); +/** + * radix_tree_iter_retry - retry this chunk of the iteration + * @iter: iterator state + * + * If we iterate over a tree protected only by the RCU lock, a race + * against deletion or creation may result in seeing a slot for which + * radix_tree_deref_retry() returns true. If so, call this function + * and continue the iteration. + */ +static inline __must_check +void **radix_tree_iter_retry(struct radix_tree_iter *iter) +{ + iter->next_index = iter->index; + return NULL; +} + /** * radix_tree_chunk_size - get current chunk size * diff --git a/lib/radix-tree.c b/lib/radix-tree.c index fcf5d98574ce..6b79e9026e24 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -1019,9 +1019,13 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results, return 0; radix_tree_for_each_slot(slot, root, &iter, first_index) { - results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); + results[ret] = rcu_dereference_raw(*slot); if (!results[ret]) continue; + if (radix_tree_is_indirect_ptr(results[ret])) { + slot = radix_tree_iter_retry(&iter); + continue; + } if (++ret == max_items) break; } @@ -1098,9 +1102,13 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, return 0; radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { - results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); + results[ret] = rcu_dereference_raw(*slot); if (!results[ret]) continue; + if (radix_tree_is_indirect_ptr(results[ret])) { + slot = radix_tree_iter_retry(&iter); + continue; + } if (++ret == max_items) break; } -- cgit v1.2.3-71-gd317 From d7ce36924344ace0dbdc855b1206cacc46b36d45 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 5 Feb 2016 15:36:16 -0800 Subject: dump_stack: avoid potential deadlocks Some servers experienced fatal deadlocks because of a combination of bugs, leading to multiple cpus calling dump_stack(). The checksumming bug was fixed in commit 34ae6a1aa054 ("ipv6: update skb->csum when CE mark is propagated"). The second problem is a faulty locking in dump_stack() CPU1 runs in process context and calls dump_stack(), grabs dump_lock. CPU2 receives a TCP packet under softirq, grabs socket spinlock, and call dump_stack() from netdev_rx_csum_fault(). dump_stack() spins on atomic_cmpxchg(&dump_lock, -1, 2), since dump_lock is owned by CPU1 While dumping its stack, CPU1 is interrupted by a softirq, and happens to process a packet for the TCP socket locked by CPU2. CPU1 spins forever in spin_lock() : deadlock Stack trace on CPU1 looked like : NMI backtrace for cpu 1 RIP: _raw_spin_lock+0x25/0x30 ... Call Trace: tcp_v6_rcv+0x243/0x620 ip6_input_finish+0x11f/0x330 ip6_input+0x38/0x40 ip6_rcv_finish+0x3c/0x90 ipv6_rcv+0x2a9/0x500 process_backlog+0x461/0xaa0 net_rx_action+0x147/0x430 __do_softirq+0x167/0x2d0 call_softirq+0x1c/0x30 do_softirq+0x3f/0x80 irq_exit+0x6e/0xc0 smp_call_function_single_interrupt+0x35/0x40 call_function_single_interrupt+0x6a/0x70 printk+0x4d/0x4f printk_address+0x31/0x33 print_trace_address+0x33/0x3c print_context_stack+0x7f/0x119 dump_trace+0x26b/0x28e show_trace_log_lvl+0x4f/0x5c show_stack_log_lvl+0x104/0x113 show_stack+0x42/0x44 dump_stack+0x46/0x58 netdev_rx_csum_fault+0x38/0x3c __skb_checksum_complete_head+0x6e/0x80 __skb_checksum_complete+0x11/0x20 tcp_rcv_established+0x2bd5/0x2fd0 tcp_v6_do_rcv+0x13c/0x620 sk_backlog_rcv+0x15/0x30 release_sock+0xd2/0x150 tcp_recvmsg+0x1c1/0xfc0 inet_recvmsg+0x7d/0x90 sock_recvmsg+0xaf/0xe0 ___sys_recvmsg+0x111/0x3b0 SyS_recvmsg+0x5c/0xb0 system_call_fastpath+0x16/0x1b Fixes: b58d977432c8 ("dump_stack: serialize the output from dump_stack()") Signed-off-by: Eric Dumazet Cc: Alex Thorlton Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/dump_stack.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/dump_stack.c b/lib/dump_stack.c index 6745c6230db3..c30d07e99dba 100644 --- a/lib/dump_stack.c +++ b/lib/dump_stack.c @@ -25,6 +25,7 @@ static atomic_t dump_lock = ATOMIC_INIT(-1); asmlinkage __visible void dump_stack(void) { + unsigned long flags; int was_locked; int old; int cpu; @@ -33,9 +34,8 @@ asmlinkage __visible void dump_stack(void) * Permit this cpu to perform nested stack dumps while serialising * against other CPUs */ - preempt_disable(); - retry: + local_irq_save(flags); cpu = smp_processor_id(); old = atomic_cmpxchg(&dump_lock, -1, cpu); if (old == -1) { @@ -43,6 +43,7 @@ retry: } else if (old == cpu) { was_locked = 1; } else { + local_irq_restore(flags); cpu_relax(); goto retry; } @@ -52,7 +53,7 @@ retry: if (!was_locked) atomic_set(&dump_lock, -1); - preempt_enable(); + local_irq_restore(flags); } #else asmlinkage __visible void dump_stack(void) -- cgit v1.2.3-71-gd317