From: kernel test robot <lkp@intel.com>
To: oe-kbuild@lists.linux.dev
Cc: lkp@intel.com, Dan Carpenter <error27@gmail.com>
Subject: [axboe:rw_iter 94/471] mm/vmscan.c:5589 lru_gen_seq_write_iter() warn: potential spectre issue 'next' [w]
Date: Sat, 07 Mar 2026 12:04:56 +0800 [thread overview]
Message-ID: <202603071159.4M3DpFDx-lkp@intel.com> (raw)
BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Jens Axboe <axboe@kernel.dk>
tree: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git rw_iter
head: 0a49759be1c3b29207758e467fdc1a90d0716d06
commit: 14b5ca45e7095f41192b0acf6b6f643f925a5cae [94/471] mm: convert to read/write iterators
:::::: branch date: 17 hours ago
:::::: commit date: 17 hours ago
config: m68k-randconfig-r073-20260307 (https://download.01.org/0day-ci/archive/20260307/202603071159.4M3DpFDx-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.5.0
smatch: v0.5.0-9004-gb810ac53
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/202603071159.4M3DpFDx-lkp@intel.com/
smatch warnings:
mm/vmscan.c:5589 lru_gen_seq_write_iter() warn: potential spectre issue 'next' [w]
vim +/next +5589 mm/vmscan.c
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5552
07017acb06012d Yu Zhao 2022-09-18 5553 /* see Documentation/admin-guide/mm/multigen_lru.rst for details */
14b5ca45e7095f Jens Axboe 2024-04-03 5554 static ssize_t lru_gen_seq_write_iter(struct kiocb *iocb, struct iov_iter *from)
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5555 {
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5556 void *buf;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5557 char *cur, *next;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5558 unsigned int flags;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5559 struct blk_plug plug;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5560 int err = -EINVAL;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5561 struct scan_control sc = {
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5562 .may_writepage = true,
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5563 .may_unmap = true,
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5564 .may_swap = true,
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5565 .reclaim_idx = MAX_NR_ZONES - 1,
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5566 .gfp_mask = GFP_KERNEL,
915a4022b591d5 Hao Jia 2025-07-17 5567 .proactive = true,
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5568 };
14b5ca45e7095f Jens Axboe 2024-04-03 5569 size_t len = iov_iter_count(from);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5570
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5571 buf = kvmalloc(len + 1, GFP_KERNEL);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5572 if (!buf)
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5573 return -ENOMEM;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5574
14b5ca45e7095f Jens Axboe 2024-04-03 5575 if (!copy_from_iter_full(buf, len, from)) {
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5576 kvfree(buf);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5577 return -EFAULT;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5578 }
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5579
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5580 set_task_reclaim_state(current, &sc.reclaim_state);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5581 flags = memalloc_noreclaim_save();
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5582 blk_start_plug(&plug);
e9d4e1ee788097 Yu Zhao 2022-12-21 5583 if (!set_mm_walk(NULL, true)) {
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5584 err = -ENOMEM;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5585 goto done;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5586 }
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5587
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5588 next = buf;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 @5589 next[len] = '\0';
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5590
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5591 while ((cur = strsep(&next, ",;\n"))) {
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5592 int n;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5593 int end;
b40599930f001b Zhongkun He 2025-04-21 5594 char cmd, swap_string[5];
20ccbd89afe425 Shakeel Butt 2025-12-25 5595 u64 memcg_id;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5596 unsigned int nid;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5597 unsigned long seq;
b40599930f001b Zhongkun He 2025-04-21 5598 unsigned int swappiness;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5599 unsigned long opt = -1;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5600
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5601 cur = skip_spaces(cur);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5602 if (!*cur)
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5603 continue;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5604
20ccbd89afe425 Shakeel Butt 2025-12-25 5605 n = sscanf(cur, "%c %llu %u %lu %n %4s %n %lu %n", &cmd, &memcg_id, &nid,
b40599930f001b Zhongkun He 2025-04-21 5606 &seq, &end, swap_string, &end, &opt, &end);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5607 if (n < 4 || cur[end]) {
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5608 err = -EINVAL;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5609 break;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5610 }
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5611
b40599930f001b Zhongkun He 2025-04-21 5612 if (n == 4) {
b40599930f001b Zhongkun He 2025-04-21 5613 swappiness = -1;
b40599930f001b Zhongkun He 2025-04-21 5614 } else if (!strcmp("max", swap_string)) {
b40599930f001b Zhongkun He 2025-04-21 5615 /* set by userspace for anonymous memory only */
b40599930f001b Zhongkun He 2025-04-21 5616 swappiness = SWAPPINESS_ANON_ONLY;
b40599930f001b Zhongkun He 2025-04-21 5617 } else {
b40599930f001b Zhongkun He 2025-04-21 5618 err = kstrtouint(swap_string, 0, &swappiness);
b40599930f001b Zhongkun He 2025-04-21 5619 if (err)
b40599930f001b Zhongkun He 2025-04-21 5620 break;
b40599930f001b Zhongkun He 2025-04-21 5621 }
b40599930f001b Zhongkun He 2025-04-21 5622
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5623 err = run_cmd(cmd, memcg_id, nid, seq, &sc, swappiness, opt);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5624 if (err)
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5625 break;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5626 }
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5627 done:
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5628 clear_mm_walk();
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5629 blk_finish_plug(&plug);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5630 memalloc_noreclaim_restore(flags);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5631 set_task_reclaim_state(current, NULL);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5632
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5633 kvfree(buf);
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5634
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5635 return err ? : len;
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5636 }
d6c3af7d8a2ba5 Yu Zhao 2022-09-18 5637
:::::: The code at line 5589 was first introduced by commit
:::::: d6c3af7d8a2ba5602c28841248c551a712ac50f5 mm: multi-gen LRU: debugfs interface
:::::: TO: Yu Zhao <yuzhao@google.com>
:::::: CC: Andrew Morton <akpm@linux-foundation.org>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
reply other threads:[~2026-03-07 4:05 UTC|newest]
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