tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git willy-maple head: 7e346d2845b4bd77663394f39fa70456e0084c86 commit: c4e6b1dfcb6f997eb870e859ab84ca9f39572eab [164/202] fs/proc/task_mmu: Stop using linked list and highest_vm_end config: x86_64-randconfig-m001-20210202 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <l...@intel.com>
Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
smatch warnings:
fs/proc/task_mmu.c:941 show_smaps_rollup() error: uninitialized symbol
'vma_start'.
vim +/vma_start +941 fs/proc/task_mmu.c
258f669e7e88c1 Vlastimil Babka 2018-08-21 839 static int
show_smaps_rollup(struct seq_file *m, void *v)
258f669e7e88c1 Vlastimil Babka 2018-08-21 840 {
258f669e7e88c1 Vlastimil Babka 2018-08-21 841 struct
proc_maps_private *priv = m->private;
258f669e7e88c1 Vlastimil Babka 2018-08-21 842 struct mem_size_stats
mss;
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 843 struct mm_struct *mm =
priv->mm;
258f669e7e88c1 Vlastimil Babka 2018-08-21 844 struct vm_area_struct
*vma;
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 845 unsigned long
vma_start, last_vma_end = 0;
258f669e7e88c1 Vlastimil Babka 2018-08-21 846 int ret = 0;
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 847 MA_STATE(mas,
&mm->mm_mt, 0, 0);
258f669e7e88c1 Vlastimil Babka 2018-08-21 848
258f669e7e88c1 Vlastimil Babka 2018-08-21 849 priv->task =
get_proc_task(priv->inode);
258f669e7e88c1 Vlastimil Babka 2018-08-21 850 if (!priv->task)
258f669e7e88c1 Vlastimil Babka 2018-08-21 851 return -ESRCH;
258f669e7e88c1 Vlastimil Babka 2018-08-21 852
258f669e7e88c1 Vlastimil Babka 2018-08-21 853 if (!mm ||
!mmget_not_zero(mm)) {
258f669e7e88c1 Vlastimil Babka 2018-08-21 854 ret = -ESRCH;
258f669e7e88c1 Vlastimil Babka 2018-08-21 855 goto
out_put_task;
258f669e7e88c1 Vlastimil Babka 2018-08-21 856 }
258f669e7e88c1 Vlastimil Babka 2018-08-21 857
258f669e7e88c1 Vlastimil Babka 2018-08-21 858 memset(&mss, 0,
sizeof(mss));
258f669e7e88c1 Vlastimil Babka 2018-08-21 859
d8ed45c5dcd455 Michel Lespinasse 2020-06-08 860 ret =
mmap_read_lock_killable(mm);
a26a9781554857 Konstantin Khlebnikov 2019-07-11 861 if (ret)
a26a9781554857 Konstantin Khlebnikov 2019-07-11 862 goto out_put_mm;
a26a9781554857 Konstantin Khlebnikov 2019-07-11 863
258f669e7e88c1 Vlastimil Babka 2018-08-21 864
hold_task_mempolicy(priv);
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 865 vma = mas_find(&mas, 0);
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 866
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 867 if (vma)
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 868 vma_start =
vma->vm_start;
"vma_start" not initialized on else path.
258f669e7e88c1 Vlastimil Babka 2018-08-21 869
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 870 mas_set(&mas, 0);
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 871 mas_for_each(&mas, vma,
-1) {
03b4b1149308b0 Chinwen Chang 2020-10-13 872
smap_gather_stats(vma, &mss, 0);
258f669e7e88c1 Vlastimil Babka 2018-08-21 873 last_vma_end =
vma->vm_end;
ff9f47f6f00cfe Chinwen Chang 2020-10-13 874
ff9f47f6f00cfe Chinwen Chang 2020-10-13 875 /*
ff9f47f6f00cfe Chinwen Chang 2020-10-13 876 * Release
mmap_lock temporarily if someone wants to
ff9f47f6f00cfe Chinwen Chang 2020-10-13 877 * access it
for write request.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 878 */
ff9f47f6f00cfe Chinwen Chang 2020-10-13 879 if
(mmap_lock_is_contended(mm)) {
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 880
mas_pause(&mas);
ff9f47f6f00cfe Chinwen Chang 2020-10-13 881
mmap_read_unlock(mm);
ff9f47f6f00cfe Chinwen Chang 2020-10-13 882 ret =
mmap_read_lock_killable(mm);
ff9f47f6f00cfe Chinwen Chang 2020-10-13 883 if
(ret) {
ff9f47f6f00cfe Chinwen Chang 2020-10-13 884
release_task_mempolicy(priv);
ff9f47f6f00cfe Chinwen Chang 2020-10-13 885
goto out_put_mm;
ff9f47f6f00cfe Chinwen Chang 2020-10-13 886 }
ff9f47f6f00cfe Chinwen Chang 2020-10-13 887
ff9f47f6f00cfe Chinwen Chang 2020-10-13 888 /*
ff9f47f6f00cfe Chinwen Chang 2020-10-13 889 *
After dropping the lock, there are four cases to
ff9f47f6f00cfe Chinwen Chang 2020-10-13 890 *
consider. See the following example for explanation.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 891 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 892 *
+------+------+-----------+
ff9f47f6f00cfe Chinwen Chang 2020-10-13 893 * |
VMA1 | VMA2 | VMA3 |
ff9f47f6f00cfe Chinwen Chang 2020-10-13 894 *
+------+------+-----------+
ff9f47f6f00cfe Chinwen Chang 2020-10-13 895 * |
| | |
ff9f47f6f00cfe Chinwen Chang 2020-10-13 896 * 4k
8k 16k 400k
ff9f47f6f00cfe Chinwen Chang 2020-10-13 897 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 898 *
Suppose we drop the lock after reading VMA2 due to
ff9f47f6f00cfe Chinwen Chang 2020-10-13 899 *
contention, then we get:
ff9f47f6f00cfe Chinwen Chang 2020-10-13 900 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 901 *
last_vma_end = 16k
ff9f47f6f00cfe Chinwen Chang 2020-10-13 902 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 903 * 1)
VMA2 is freed, but VMA3 exists:
ff9f47f6f00cfe Chinwen Chang 2020-10-13 904 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 905 *
find_vma(mm, 16k - 1) will return VMA3.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 906 *
In this case, just continue from VMA3.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 907 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 908 * 2)
VMA2 still exists:
ff9f47f6f00cfe Chinwen Chang 2020-10-13 909 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 910 *
find_vma(mm, 16k - 1) will return VMA2.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 911 *
Iterate the loop like the original one.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 912 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 913 * 3)
No more VMAs can be found:
ff9f47f6f00cfe Chinwen Chang 2020-10-13 914 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 915 *
find_vma(mm, 16k - 1) will return NULL.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 916 *
No more things to do, just break.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 917 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 918 * 4)
(last_vma_end - 1) is the middle of a vma (VMA'):
ff9f47f6f00cfe Chinwen Chang 2020-10-13 919 *
ff9f47f6f00cfe Chinwen Chang 2020-10-13 920 *
find_vma(mm, 16k - 1) will return VMA' whose range
ff9f47f6f00cfe Chinwen Chang 2020-10-13 921 *
contains last_vma_end.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 922 *
Iterate VMA' from last_vma_end.
ff9f47f6f00cfe Chinwen Chang 2020-10-13 923 */
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 924
mas.index = mas.last = last_vma_end - 1;
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 925 vma =
mas_find(&mas, -1);
ff9f47f6f00cfe Chinwen Chang 2020-10-13 926 /* Case
3 above */
ff9f47f6f00cfe Chinwen Chang 2020-10-13 927 if
(!vma)
ff9f47f6f00cfe Chinwen Chang 2020-10-13 928
break;
ff9f47f6f00cfe Chinwen Chang 2020-10-13 929
ff9f47f6f00cfe Chinwen Chang 2020-10-13 930 /* Case
1 above */
ff9f47f6f00cfe Chinwen Chang 2020-10-13 931 if
(vma->vm_start >= last_vma_end)
ff9f47f6f00cfe Chinwen Chang 2020-10-13 932
continue;
ff9f47f6f00cfe Chinwen Chang 2020-10-13 933
ff9f47f6f00cfe Chinwen Chang 2020-10-13 934 /* Case
4 above */
ff9f47f6f00cfe Chinwen Chang 2020-10-13 935 if
(vma->vm_end > last_vma_end)
ff9f47f6f00cfe Chinwen Chang 2020-10-13 936
smap_gather_stats(vma, &mss, last_vma_end);
ff9f47f6f00cfe Chinwen Chang 2020-10-13 937 }
ff9f47f6f00cfe Chinwen Chang 2020-10-13 938 /* Case 2 above
*/
258f669e7e88c1 Vlastimil Babka 2018-08-21 939 }
258f669e7e88c1 Vlastimil Babka 2018-08-21 940
c4e6b1dfcb6f99 Liam R. Howlett 2021-01-04 @941
show_vma_header_prefix(m, vma_start, last_vma_end, 0, 0, 0, 0);
^^^^^^^^^
Uninitialized.
258f669e7e88c1 Vlastimil Babka 2018-08-21 942 seq_pad(m, ' ');
258f669e7e88c1 Vlastimil Babka 2018-08-21 943 seq_puts(m,
"[rollup]\n");
258f669e7e88c1 Vlastimil Babka 2018-08-21 944
ee2ad71b0756e9 Luigi Semenzato 2019-07-11 945 __show_smap(m, &mss,
true);
258f669e7e88c1 Vlastimil Babka 2018-08-21 946
258f669e7e88c1 Vlastimil Babka 2018-08-21 947
release_task_mempolicy(priv);
d8ed45c5dcd455 Michel Lespinasse 2020-06-08 948 mmap_read_unlock(mm);
258f669e7e88c1 Vlastimil Babka 2018-08-21 949
a26a9781554857 Konstantin Khlebnikov 2019-07-11 950 out_put_mm:
a26a9781554857 Konstantin Khlebnikov 2019-07-11 951 mmput(mm);
258f669e7e88c1 Vlastimil Babka 2018-08-21 952 out_put_task:
258f669e7e88c1 Vlastimil Babka 2018-08-21 953
put_task_struct(priv->task);
258f669e7e88c1 Vlastimil Babka 2018-08-21 954 priv->task = NULL;
258f669e7e88c1 Vlastimil Babka 2018-08-21 955
493b0e9d945fa9 Daniel Colascione 2017-09-06 956 return ret;
e070ad49f31155 Mauricio Lin 2005-09-03 957 }
---
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https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org
.config.gz
Description: application/gzip
