From: kernel test robot <lkp@intel.com>
To: oe-kbuild@lists.linux.dev
Cc: lkp@intel.com, Dan Carpenter <error27@gmail.com>
Subject: [linux-next:master 7224/7423] fs/btrfs/extent_io.c:1125 can_skip_one_ordered_range() error: 'folio' dereferencing possible ERR_PTR()
Date: Tue, 4 Mar 2025 02:05:40 +0800 [thread overview]
Message-ID: <202503040153.la3WrwKZ-lkp@intel.com> (raw)
BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Christian Brauner <brauner@kernel.org>
tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head: cd3215bbcb9d4321def93fea6cfad4d5b42b9d1d
commit: 343a7c425f5ffba8fa977602f33d5a90a771e099 [7224/7423] Merge branch 'vfs.all' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
:::::: branch date: 10 hours ago
:::::: commit date: 4 days ago
config: x86_64-randconfig-161-20250303 (https://download.01.org/0day-ci/archive/20250304/202503040153.la3WrwKZ-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202503040153.la3WrwKZ-lkp@intel.com/
smatch warnings:
fs/btrfs/extent_io.c:1125 can_skip_one_ordered_range() error: 'folio' dereferencing possible ERR_PTR()
vim +/folio +1125 fs/btrfs/extent_io.c
d1310b2e0cd98e Chris Mason 2008-01-24 1074
f47168d051203f Qu Wenruo 2025-02-12 1075 /*
f47168d051203f Qu Wenruo 2025-02-12 1076 * Check if we can skip waiting the @ordered extent covering the block
f47168d051203f Qu Wenruo 2025-02-12 1077 * at file pos @cur.
f47168d051203f Qu Wenruo 2025-02-12 1078 *
f47168d051203f Qu Wenruo 2025-02-12 1079 * Return true if we can skip to @next_ret. The caller needs to check
f47168d051203f Qu Wenruo 2025-02-12 1080 * the @next_ret value to make sure if covers the full range, before
f47168d051203f Qu Wenruo 2025-02-12 1081 * skipping the OE.
f47168d051203f Qu Wenruo 2025-02-12 1082 *
f47168d051203f Qu Wenruo 2025-02-12 1083 * Return false if we must wait for the ordered extent.
f47168d051203f Qu Wenruo 2025-02-12 1084 *
f47168d051203f Qu Wenruo 2025-02-12 1085 * @cur: The start file offset that we have locked folio for read.
f47168d051203f Qu Wenruo 2025-02-12 1086 * @next_ret: If we return true, this indiciates the next check start
f47168d051203f Qu Wenruo 2025-02-12 1087 * range.
f47168d051203f Qu Wenruo 2025-02-12 1088 */
f47168d051203f Qu Wenruo 2025-02-12 1089 static bool can_skip_one_ordered_range(struct btrfs_inode *binode,
f47168d051203f Qu Wenruo 2025-02-12 1090 struct btrfs_ordered_extent *ordered,
f47168d051203f Qu Wenruo 2025-02-12 1091 u64 cur, u64 *next_ret)
f47168d051203f Qu Wenruo 2025-02-12 1092 {
f47168d051203f Qu Wenruo 2025-02-12 1093 const struct btrfs_fs_info *fs_info = binode->root->fs_info;
f47168d051203f Qu Wenruo 2025-02-12 1094 struct folio *folio;
f47168d051203f Qu Wenruo 2025-02-12 1095 const u32 blocksize = fs_info->sectorsize;
f47168d051203f Qu Wenruo 2025-02-12 1096 u64 range_len;
f47168d051203f Qu Wenruo 2025-02-12 1097 bool ret;
f47168d051203f Qu Wenruo 2025-02-12 1098
f47168d051203f Qu Wenruo 2025-02-12 1099 folio = filemap_get_folio(binode->vfs_inode.i_mapping,
f47168d051203f Qu Wenruo 2025-02-12 1100 cur >> PAGE_SHIFT);
f47168d051203f Qu Wenruo 2025-02-12 1101
f47168d051203f Qu Wenruo 2025-02-12 1102 /*
f47168d051203f Qu Wenruo 2025-02-12 1103 * We should have locked the folio(s) for range [start, end], thus
f47168d051203f Qu Wenruo 2025-02-12 1104 * there must be a folio and it must be locked.
f47168d051203f Qu Wenruo 2025-02-12 1105 */
f47168d051203f Qu Wenruo 2025-02-12 1106 ASSERT(!IS_ERR(folio));
f47168d051203f Qu Wenruo 2025-02-12 1107 ASSERT(folio_test_locked(folio));
f47168d051203f Qu Wenruo 2025-02-12 1108
f47168d051203f Qu Wenruo 2025-02-12 1109 /*
f47168d051203f Qu Wenruo 2025-02-12 1110 * We several cases for the folio and OE combination:
f47168d051203f Qu Wenruo 2025-02-12 1111 *
f47168d051203f Qu Wenruo 2025-02-12 1112 * 0) Folio has no private flag
f47168d051203f Qu Wenruo 2025-02-12 1113 * The OE has all its IO done but not yet finished, and folio got
f47168d051203f Qu Wenruo 2025-02-12 1114 * invalidated. Or direct IO.
f47168d051203f Qu Wenruo 2025-02-12 1115 *
f47168d051203f Qu Wenruo 2025-02-12 1116 * Have to wait for the OE to finish, as it may contain the
f47168d051203f Qu Wenruo 2025-02-12 1117 * to-be-inserted data checksum.
f47168d051203f Qu Wenruo 2025-02-12 1118 * Without the data checksum inserted into csum tree, read
f47168d051203f Qu Wenruo 2025-02-12 1119 * will just fail with missing csum.
f47168d051203f Qu Wenruo 2025-02-12 1120 */
f47168d051203f Qu Wenruo 2025-02-12 1121 if (!folio_test_private(folio)) {
f47168d051203f Qu Wenruo 2025-02-12 1122 ret = false;
f47168d051203f Qu Wenruo 2025-02-12 1123 goto out;
f47168d051203f Qu Wenruo 2025-02-12 1124 }
f47168d051203f Qu Wenruo 2025-02-12 @1125 range_len = min(folio_pos(folio) + folio_size(folio),
f47168d051203f Qu Wenruo 2025-02-12 1126 ordered->file_offset + ordered->num_bytes) - cur;
f47168d051203f Qu Wenruo 2025-02-12 1127
f47168d051203f Qu Wenruo 2025-02-12 1128 /*
f47168d051203f Qu Wenruo 2025-02-12 1129 * 1) The first block is DIRTY.
f47168d051203f Qu Wenruo 2025-02-12 1130 *
f47168d051203f Qu Wenruo 2025-02-12 1131 * This means the OE is created by some folio before us, but writeback
f47168d051203f Qu Wenruo 2025-02-12 1132 * has not started.
f47168d051203f Qu Wenruo 2025-02-12 1133 * We can and must skip the whole OE, because it will never start until
f47168d051203f Qu Wenruo 2025-02-12 1134 * we finished our folio read and unlocked the folio.
f47168d051203f Qu Wenruo 2025-02-12 1135 */
f47168d051203f Qu Wenruo 2025-02-12 1136 if (btrfs_folio_test_dirty(fs_info, folio, cur, blocksize)) {
f47168d051203f Qu Wenruo 2025-02-12 1137 ret = true;
f47168d051203f Qu Wenruo 2025-02-12 1138 /*
f47168d051203f Qu Wenruo 2025-02-12 1139 * At least inside the folio, all the remaining blocks should
f47168d051203f Qu Wenruo 2025-02-12 1140 * also be dirty.
f47168d051203f Qu Wenruo 2025-02-12 1141 */
f47168d051203f Qu Wenruo 2025-02-12 1142 ASSERT(btrfs_folio_test_dirty(fs_info, folio, cur, range_len));
f47168d051203f Qu Wenruo 2025-02-12 1143 *next_ret = ordered->file_offset + ordered->num_bytes;
f47168d051203f Qu Wenruo 2025-02-12 1144 goto out;
f47168d051203f Qu Wenruo 2025-02-12 1145 }
f47168d051203f Qu Wenruo 2025-02-12 1146
f47168d051203f Qu Wenruo 2025-02-12 1147 /*
f47168d051203f Qu Wenruo 2025-02-12 1148 * 2) The first block is uptodate.
f47168d051203f Qu Wenruo 2025-02-12 1149 *
f47168d051203f Qu Wenruo 2025-02-12 1150 * At least the first block can be skipped, but we are still
f47168d051203f Qu Wenruo 2025-02-12 1151 * not full sure. E.g. if the OE has some other folios in
f47168d051203f Qu Wenruo 2025-02-12 1152 * the range that can not be skipped.
f47168d051203f Qu Wenruo 2025-02-12 1153 * So we return true and update @next_ret to the OE/folio boundary.
f47168d051203f Qu Wenruo 2025-02-12 1154 */
f47168d051203f Qu Wenruo 2025-02-12 1155 if (btrfs_folio_test_uptodate(fs_info, folio, cur, blocksize)) {
f47168d051203f Qu Wenruo 2025-02-12 1156 u64 range_len = min(folio_pos(folio) + folio_size(folio),
f47168d051203f Qu Wenruo 2025-02-12 1157 ordered->file_offset + ordered->num_bytes) - cur;
f47168d051203f Qu Wenruo 2025-02-12 1158
f47168d051203f Qu Wenruo 2025-02-12 1159 /*
f47168d051203f Qu Wenruo 2025-02-12 1160 * The whole range to the OE end or folio boundary should also
f47168d051203f Qu Wenruo 2025-02-12 1161 * be uptodate.
f47168d051203f Qu Wenruo 2025-02-12 1162 */
f47168d051203f Qu Wenruo 2025-02-12 1163 ASSERT(btrfs_folio_test_uptodate(fs_info, folio, cur, range_len));
f47168d051203f Qu Wenruo 2025-02-12 1164 ret = true;
f47168d051203f Qu Wenruo 2025-02-12 1165 *next_ret = cur + range_len;
f47168d051203f Qu Wenruo 2025-02-12 1166 goto out;
f47168d051203f Qu Wenruo 2025-02-12 1167 }
f47168d051203f Qu Wenruo 2025-02-12 1168
f47168d051203f Qu Wenruo 2025-02-12 1169 /*
f47168d051203f Qu Wenruo 2025-02-12 1170 * 3) The first block is not uptodate.
f47168d051203f Qu Wenruo 2025-02-12 1171 *
f47168d051203f Qu Wenruo 2025-02-12 1172 * This means the folio is invalidated after the OE finished, or direct IO.
f47168d051203f Qu Wenruo 2025-02-12 1173 * Very much the same as case 1), just with private flag set.
f47168d051203f Qu Wenruo 2025-02-12 1174 */
f47168d051203f Qu Wenruo 2025-02-12 1175 ret = false;
f47168d051203f Qu Wenruo 2025-02-12 1176 out:
f47168d051203f Qu Wenruo 2025-02-12 1177 folio_put(folio);
f47168d051203f Qu Wenruo 2025-02-12 1178 return ret;
f47168d051203f Qu Wenruo 2025-02-12 1179 }
f47168d051203f Qu Wenruo 2025-02-12 1180
:::::: The code at line 1125 was first introduced by commit
:::::: f47168d051203f5f9020ee51ef8c90db89008fe0 btrfs: introduce a read path dedicated extent lock helper
:::::: TO: Qu Wenruo <wqu@suse.com>
:::::: CC: David Sterba <dsterba@suse.com>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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