Hi Jérôme, I love your patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v4.20-rc6 next-20181214] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/jglisse-redhat-com/dma-buf-fix-debugfs-versus-rcu-and-fence-dumping/20181206-205935 config: x86_64-allmodconfig (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All warnings (new ones prefixed by >>): include/linux/slab.h:332:43: warning: dubious: x & !y include/linux/slab.h:332:43: warning: dubious: x & !y >> drivers/dma-buf/dma-buf.c:1031:9: warning: context imbalance in 'dma_buf_debug_show' - different lock contexts for basic block vim +/dma_buf_debug_show +1031 drivers/dma-buf/dma-buf.c b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1008 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1009 #ifdef CONFIG_DEBUG_FS eb0b947e drivers/dma-buf/dma-buf.c Mathias Krause 2016-06-19 1010 static int dma_buf_debug_show(struct seq_file *s, void *unused) b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1011 { b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1012 int ret; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1013 struct dma_buf *buf_obj; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1014 struct dma_buf_attachment *attach_obj; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1015 struct reservation_object *robj; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1016 struct reservation_object_list *fobj; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1017 struct dma_fence *fence; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1018 unsigned seq; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1019 int count = 0, attach_count, shared_count, i; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1020 size_t size = 0; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1021 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1022 ret = mutex_lock_interruptible(&db_list.lock); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1023 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1024 if (ret) b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1025 return ret; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1026 c0b00a52 drivers/base/dma-buf.c Sumit Semwal 2014-02-03 1027 seq_puts(s, "\nDma-buf Objects:\n"); da6c8f5e drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1028 seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\n", da6c8f5e drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1029 "size", "flags", "mode", "count"); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1030 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 @1031 list_for_each_entry(buf_obj, &db_list.head, list_node) { b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1032 ret = mutex_lock_interruptible(&buf_obj->lock); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1033 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1034 if (ret) { c0b00a52 drivers/base/dma-buf.c Sumit Semwal 2014-02-03 1035 seq_puts(s, b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1036 "\tERROR locking buffer object: skipping\n"); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1037 continue; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1038 } b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1039 c0b00a52 drivers/base/dma-buf.c Sumit Semwal 2014-02-03 1040 seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n", c0b00a52 drivers/base/dma-buf.c Sumit Semwal 2014-02-03 1041 buf_obj->size, b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1042 buf_obj->file->f_flags, buf_obj->file->f_mode, a1f6dbac drivers/dma-buf/dma-buf.c Al Viro 2014-08-20 1043 file_count(buf_obj->file), c0b00a52 drivers/base/dma-buf.c Sumit Semwal 2014-02-03 1044 buf_obj->exp_name); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1045 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1046 robj = buf_obj->resv; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1047 while (true) { 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1048 seq = read_seqcount_begin(&robj->seq); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1049 rcu_read_lock(); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1050 fobj = rcu_dereference(robj->fence); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1051 shared_count = fobj ? fobj->shared_count : 0; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1052 fence = rcu_dereference(robj->fence_excl); 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1053 fence = dma_fence_get_rcu(fence); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1054 if (!read_seqcount_retry(&robj->seq, seq)) 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1055 break; 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1056 rcu_read_unlock(); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1057 } 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1058 if (fence) { 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1059 seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1060 fence->ops->get_driver_name(fence), 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1061 fence->ops->get_timeline_name(fence), 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1062 dma_fence_is_signaled(fence) ? "" : "un"); 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1063 dma_fence_put(fence); 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1064 } 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1065 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1066 rcu_read_lock(); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1067 for (i = 0; i < shared_count; i++) { 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1068 fence = rcu_dereference(fobj->shared[i]); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1069 if (!dma_fence_get_rcu(fence)) 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1070 continue; 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1071 rcu_read_unlock(); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1072 seq_printf(s, "\tShared fence: %s %s %ssignalled\n", 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1073 fence->ops->get_driver_name(fence), 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1074 fence->ops->get_timeline_name(fence), 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1075 dma_fence_is_signaled(fence) ? "" : "un"); 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1076 dma_fence_put(fence); 87e66c10 drivers/dma-buf/dma-buf.c Jérôme Glisse 2018-12-05 1077 rcu_read_lock(); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1078 } 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1079 rcu_read_unlock(); 5eb2c72c drivers/dma-buf/dma-buf.c Russell King 2017-03-31 1080 c0b00a52 drivers/base/dma-buf.c Sumit Semwal 2014-02-03 1081 seq_puts(s, "\tAttached Devices:\n"); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1082 attach_count = 0; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1083 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1084 list_for_each_entry(attach_obj, &buf_obj->attachments, node) { 9eddb41d drivers/dma-buf/dma-buf.c Markus Elfring 2017-05-08 1085 seq_printf(s, "\t%s\n", dev_name(attach_obj->dev)); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1086 attach_count++; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1087 } b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1088 c0b00a52 drivers/base/dma-buf.c Sumit Semwal 2014-02-03 1089 seq_printf(s, "Total %d devices attached\n\n", b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1090 attach_count); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1091 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1092 count++; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1093 size += buf_obj->size; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1094 mutex_unlock(&buf_obj->lock); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1095 } b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1096 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1097 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1098 b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1099 mutex_unlock(&db_list.lock); b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1100 return 0; b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1101 } b89e3563 drivers/base/dma-buf.c Sumit Semwal 2013-04-04 1102 :::::: The code at line 1031 was first introduced by commit :::::: b89e35636bc75b72d15a1af6d49798802aff77d5 dma-buf: Add debugfs support :::::: TO: Sumit Semwal <sumit.semwal@xxxxxxxxxx> :::::: CC: Sumit Semwal <sumit.semwal@xxxxxxxxxx> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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