fs/select.c:970:12: warning: stack frame size of 1032 bytes in function 'do_sys_poll'

From: kernel test robot
Date: Sat Mar 20 2021 - 11:00:31 EST

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tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 1c273e10bc0cc7efb933e0ca10e260cdfc9f0b8c
commit: 8b3165e54566e8bb8f4b7d4e5f12ced78ce462bb MIPS: Enable GCOV
date: 4 months ago
config: mips-randconfig-r022-20210320 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 436c6c9c20cc522c92a923440a5fc509c342a7db)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8b3165e54566e8bb8f4b7d4e5f12ced78ce462bb
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 8b3165e54566e8bb8f4b7d4e5f12ced78ce462bb
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

fs/select.c:621:5: warning: stack frame size of 1032 bytes in function 'core_sys_select' [-Wframe-larger-than=]
int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
^
>> fs/select.c:970:12: warning: stack frame size of 1032 bytes in function 'do_sys_poll' [-Wframe-larger-than=]
static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
^
2 warnings generated.

vim +/do_sys_poll +970 fs/select.c

^1da177e4c3f41 Linus Torvalds 2005-04-16 966
70674f95c0a2ea Andi Kleen 2006-03-28 967 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
70674f95c0a2ea Andi Kleen 2006-03-28 968 sizeof(struct pollfd))
70674f95c0a2ea Andi Kleen 2006-03-28 969
e99ca56ce03dd9 Al Viro 2017-04-08 @970 static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
766b9f928bd5b9 Deepa Dinamani 2016-05-19 971 struct timespec64 *end_time)
^1da177e4c3f41 Linus Torvalds 2005-04-16 972 {
^1da177e4c3f41 Linus Torvalds 2005-04-16 973 struct poll_wqueues table;
43e11fa2d1d3b6 Gustavo A. R. Silva 2019-07-16 974 int err = -EFAULT, fdcount, len;
30c14e40ed8546 Jes Sorensen 2006-03-31 975 /* Allocate small arguments on the stack to save memory and be
30c14e40ed8546 Jes Sorensen 2006-03-31 976 faster - use long to make sure the buffer is aligned properly
30c14e40ed8546 Jes Sorensen 2006-03-31 977 on 64 bit archs to avoid unaligned access */
30c14e40ed8546 Jes Sorensen 2006-03-31 978 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
252e5725cfb55a Oleg Nesterov 2007-10-16 979 struct poll_list *const head = (struct poll_list *)stack_pps;
252e5725cfb55a Oleg Nesterov 2007-10-16 980 struct poll_list *walk = head;
252e5725cfb55a Oleg Nesterov 2007-10-16 981 unsigned long todo = nfds;
^1da177e4c3f41 Linus Torvalds 2005-04-16 982
d554ed895dc8f2 Jiri Slaby 2010-03-05 983 if (nfds > rlimit(RLIMIT_NOFILE))
^1da177e4c3f41 Linus Torvalds 2005-04-16 984 return -EINVAL;
^1da177e4c3f41 Linus Torvalds 2005-04-16 985
252e5725cfb55a Oleg Nesterov 2007-10-16 986 len = min_t(unsigned int, nfds, N_STACK_PPS);
252e5725cfb55a Oleg Nesterov 2007-10-16 987 for (;;) {
252e5725cfb55a Oleg Nesterov 2007-10-16 988 walk->next = NULL;
252e5725cfb55a Oleg Nesterov 2007-10-16 989 walk->len = len;
252e5725cfb55a Oleg Nesterov 2007-10-16 990 if (!len)
252e5725cfb55a Oleg Nesterov 2007-10-16 991 break;
^1da177e4c3f41 Linus Torvalds 2005-04-16 992
252e5725cfb55a Oleg Nesterov 2007-10-16 993 if (copy_from_user(walk->entries, ufds + nfds-todo,
252e5725cfb55a Oleg Nesterov 2007-10-16 994 sizeof(struct pollfd) * walk->len))
^1da177e4c3f41 Linus Torvalds 2005-04-16 995 goto out_fds;
^1da177e4c3f41 Linus Torvalds 2005-04-16 996
252e5725cfb55a Oleg Nesterov 2007-10-16 997 todo -= walk->len;
252e5725cfb55a Oleg Nesterov 2007-10-16 998 if (!todo)
252e5725cfb55a Oleg Nesterov 2007-10-16 999 break;
252e5725cfb55a Oleg Nesterov 2007-10-16 1000
252e5725cfb55a Oleg Nesterov 2007-10-16 1001 len = min(todo, POLLFD_PER_PAGE);
43e11fa2d1d3b6 Gustavo A. R. Silva 2019-07-16 1002 walk = walk->next = kmalloc(struct_size(walk, entries, len),
43e11fa2d1d3b6 Gustavo A. R. Silva 2019-07-16 1003 GFP_KERNEL);
252e5725cfb55a Oleg Nesterov 2007-10-16 1004 if (!walk) {
252e5725cfb55a Oleg Nesterov 2007-10-16 1005 err = -ENOMEM;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1006 goto out_fds;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1007 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 1008 }
9f72949f679df0 David Woodhouse 2006-01-18 1009
252e5725cfb55a Oleg Nesterov 2007-10-16 1010 poll_initwait(&table);
ccec5ee302d5cb Mateusz Guzik 2016-01-06 1011 fdcount = do_poll(head, &table, end_time);
252e5725cfb55a Oleg Nesterov 2007-10-16 1012 poll_freewait(&table);
^1da177e4c3f41 Linus Torvalds 2005-04-16 1013
252e5725cfb55a Oleg Nesterov 2007-10-16 1014 for (walk = head; walk; walk = walk->next) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 1015 struct pollfd *fds = walk->entries;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1016 int j;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1017
252e5725cfb55a Oleg Nesterov 2007-10-16 1018 for (j = 0; j < walk->len; j++, ufds++)
^1da177e4c3f41 Linus Torvalds 2005-04-16 1019 if (__put_user(fds[j].revents, &ufds->revents))
^1da177e4c3f41 Linus Torvalds 2005-04-16 1020 goto out_fds;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1021 }
252e5725cfb55a Oleg Nesterov 2007-10-16 1022
^1da177e4c3f41 Linus Torvalds 2005-04-16 1023 err = fdcount;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1024 out_fds:
252e5725cfb55a Oleg Nesterov 2007-10-16 1025 walk = head->next;
252e5725cfb55a Oleg Nesterov 2007-10-16 1026 while (walk) {
252e5725cfb55a Oleg Nesterov 2007-10-16 1027 struct poll_list *pos = walk;
252e5725cfb55a Oleg Nesterov 2007-10-16 1028 walk = walk->next;
252e5725cfb55a Oleg Nesterov 2007-10-16 1029 kfree(pos);
^1da177e4c3f41 Linus Torvalds 2005-04-16 1030 }
252e5725cfb55a Oleg Nesterov 2007-10-16 1031
^1da177e4c3f41 Linus Torvalds 2005-04-16 1032 return err;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1033 }
9f72949f679df0 David Woodhouse 2006-01-18 1034

:::::: The code at line 970 was first introduced by commit
:::::: e99ca56ce03dd90991025878152bae8b53484147 move compat select-related syscalls to fs/select.c

:::::: TO: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
:::::: CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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Next message: John Wood: "Re: [PATCH v6 2/8] security/brute: Define a LSM and manage statistical data"
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