* [dhowells-fs:netfs-crypt 49/49] fs/netfs/direct_write.c:128:7: warning: variable 'fpos2' is used uninitialized whenever 'if' condition is true
@ 2026-09-04 22:51 kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2026-09-04 22:51 UTC (permalink / raw)
To: David Howells; +Cc: oe-kbuild-all
tree: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git netfs-crypt
head: cd7c017395defe44d80f4fb480dfec5e3772ea53
commit: cd7c017395defe44d80f4fb480dfec5e3772ea53 [49/49] netfs: Support encryption on unbuffered/DIO write
config: x86_64-allmodconfig (https://download.01.org/0day-ci/archive/20260905/202609050006.JGpiRJKU-lkp@intel.com/config)
compiler: clang version 22.1.8 (https://github.com/llvm/llvm-project ca7933e47d3a3451d81e72ac174dcb5aa28b59d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260905/202609050006.JGpiRJKU-lkp@intel.com/reproduce)
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>
| Closes: https://lore.kernel.org/oe-kbuild-all/202609050006.JGpiRJKU-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> fs/netfs/direct_write.c:128:7: warning: variable 'fpos2' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
128 | if (before && part <= 2 * PAGE_SIZE) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/netfs/direct_write.c:171:53: note: uninitialized use occurs here
171 | ret = netfs_rmw_read(wreq, before ?: after, fpos1, fpos2);
| ^~~~~
fs/netfs/direct_write.c:128:3: note: remove the 'if' if its condition is always false
128 | if (before && part <= 2 * PAGE_SIZE) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
129 | struct bvecq *bq;
| ~~~~~~~~~~~~~~~~~
130 | size_t page0 = PAGE_SIZE - before->bv[0].bv_offset;
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
131 | int slot;
| ~~~~~~~~~
132 |
133 | if (part <= page0) {
| ~~~~~~~~~~~~~~~~~~~~
134 | before->bv[0].bv_len = part;
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
135 | bvecq_filled_to(before, 1);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~
136 | goto do_it;
| ~~~~~~~~~~~
137 | }
| ~
138 |
139 | bq = wreq->encrypt_cursor.bvecq;
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
140 | slot = wreq->encrypt_cursor.slot + 1;
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
141 | if (slot > bq->nr_slots) {
| ~~~~~~~~~~~~~~~~~~~~~~~~~~
142 | bq = bq->next;
| ~~~~~~~~~~~~~~
143 | slot = 0;
| ~~~~~~~~~
>> fs/netfs/direct_write.c:125:6: warning: variable 'fpos2' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
125 | if (to == end && subreq->start + subreq->len < to) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/netfs/direct_write.c:171:53: note: uninitialized use occurs here
171 | ret = netfs_rmw_read(wreq, before ?: after, fpos1, fpos2);
| ^~~~~
fs/netfs/direct_write.c:125:2: note: remove the 'if' if its condition is always true
125 | if (to == end && subreq->start + subreq->len < to) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> fs/netfs/direct_write.c:125:6: warning: variable 'fpos2' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized]
125 | if (to == end && subreq->start + subreq->len < to) {
| ^~~~~~~~~
fs/netfs/direct_write.c:171:53: note: uninitialized use occurs here
171 | ret = netfs_rmw_read(wreq, before ?: after, fpos1, fpos2);
| ^~~~~
fs/netfs/direct_write.c:125:6: note: remove the '&&' if its condition is always true
125 | if (to == end && subreq->start + subreq->len < to) {
| ^~~~~~~~~~~~
fs/netfs/direct_write.c:103:21: note: initialize the variable 'fpos2' to silence this warning
103 | uoff_t fpos1, fpos2;
| ^
| = 0
>> fs/netfs/direct_write.c:566:22: warning: variable 'ret' is uninitialized when used here [-Wuninitialized]
566 | stream->buffered = ret;
| ^~~
fs/netfs/direct_write.c:478:13: note: initialize the variable 'ret' to silence this warning
478 | ssize_t ret, n;
| ^
| = 0
4 warnings generated.
vim +128 fs/netfs/direct_write.c
93
94 /*
95 * Read gaps at either end of the bounce buffer that need to be filled for an
96 * RMW cycle.
97 */
98 static ssize_t netfs_unbuffered_rmw(struct netfs_io_request *wreq,
99 struct netfs_io_subrequest *subreq,
100 uoff_t to, uoff_t end)
101 {
102 struct bvecq *before = NULL, *after = NULL;
103 uoff_t fpos1, fpos2;
104 size_t bsize = wreq->crypto_bsize;
105 int ret;
106
107 _enter("%llx,%llx", to, end);
108
109 /* Build a buffer chain to cover the gaps. If we have two gaps, they
110 * must be discontiguous and so we will need two separate bvecqs for
111 * that; however, if the entire write spans at most two pages, just do
112 * one read for both gaps plus the middle.
113 */
114 if (subreq->start < wreq->start) {
115 before = bvecq_alloc_one(2, wreq->gfp, false);
116 if (!before)
117 return -ENOMEM;
118 fpos1 = subreq->start;
119 before->bv[0] = wreq->encrypt_cursor.bvecq->bv[wreq->encrypt_cursor.slot];
120 before->bv[0].bv_offset += wreq->encrypt_cursor.offset;
121 before->bv[0].bv_len = bsize;
122 bvecq_filled_to(before, 1);
123 }
124
> 125 if (to == end && subreq->start + subreq->len < to) {
126 size_t part = end - subreq->start;
127
> 128 if (before && part <= 2 * PAGE_SIZE) {
129 struct bvecq *bq;
130 size_t page0 = PAGE_SIZE - before->bv[0].bv_offset;
131 int slot;
132
133 if (part <= page0) {
134 before->bv[0].bv_len = part;
135 bvecq_filled_to(before, 1);
136 goto do_it;
137 }
138
139 bq = wreq->encrypt_cursor.bvecq;
140 slot = wreq->encrypt_cursor.slot + 1;
141 if (slot > bq->nr_slots) {
142 bq = bq->next;
143 slot = 0;
144 }
145
146 before->bv[0].bv_len = page0;
147 before->bv[1] = bq->bv[slot];
148 before->bv[1].bv_len = part - page0;
149 bvecq_filled_to(before, 2);
150 goto do_it;
151 }
152
153 after = bvecq_alloc_one(1, wreq->gfp, false);
154 if (!after) {
155 ret = -ENOMEM;
156 goto out;
157 }
158 fpos2 = to - bsize;
159 after->bv[0] = wreq->bounce_alloc.bvecq->bv[wreq->bounce_alloc.slot];
160 after->bv[0].bv_offset = to & (PAGE_SIZE - 1);
161 after->bv[0].bv_len = bsize;
162 bvecq_filled_to(after, 1);
163 }
164
165 if (before && after) {
166 before->next = after;
167 after->prev = before;
168 }
169
170 do_it:
171 ret = netfs_rmw_read(wreq, before ?: after, fpos1, fpos2);
172
173 out:
174 bvecq_put(before ?: after);
175 return ret;
176 }
177
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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2026-09-04 22:51 [dhowells-fs:netfs-crypt 49/49] fs/netfs/direct_write.c:128:7: warning: variable 'fpos2' is used uninitialized whenever 'if' condition is true kernel test robot
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