Subject: Re: [PATCH v2] posix-timers: add multi_clock_gettime system call

From: kernel test robot <[email-masked]>
Date: Tue, 28 Nov 2023 19:45:04 +0800

Hi Sagi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on arnd-asm-generic/master]
[also build test WARNING on tip/timers/core linus/master v6.7-rc3]
[cannot apply to tip/x86/asm next-20231128]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sagi-Maimon/posix-timers-add-multi_clock_gettime-system-call/20231128-000215
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git master
patch link:    https://lore.kernel.org/r/20231127153901.6399-1-maimon.sagi%40gmail.com
patch subject: [PATCH v2] posix-timers: add multi_clock_gettime system call
config: um-allmodconfig (https://download.01.org/0day-ci/archive/20231128/[email-masked]/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231128/[email-masked]/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 <[email-masked]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/

All warnings (new ones prefixed by >>):

   In file included from kernel/time/posix-timers.c:13:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from kernel/time/posix-timers.c:13:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from kernel/time/posix-timers.c:13:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     692 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     700 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     708 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     717 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     726 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     735 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
>> kernel/time/posix-timers.c:1429:1: warning: stack frame size (2040) exceeds limit (1024) in '__se_sys_multi_clock_gettime' [-Wframe-larger-than]
    1429 | SYSCALL_DEFINE1(multi_clock_gettime, struct __ptp_multi_clock_get __user *, ptp_multi_clk_get)
         | ^
   include/linux/syscalls.h:219:36: note: expanded from macro 'SYSCALL_DEFINE1'
     219 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
         |                                    ^
   include/linux/syscalls.h:230:2: note: expanded from macro 'SYSCALL_DEFINEx'
     230 |         __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
         |         ^
   include/linux/syscalls.h:249:18: note: expanded from macro '__SYSCALL_DEFINEx'
     249 |         asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))  \
         |                         ^
   <scratch space>:122:1: note: expanded from here
     122 | __se_sys_multi_clock_gettime
         | ^
>> kernel/time/posix-timers.c:1460:1: warning: stack frame size (2040) exceeds limit (1024) in '__se_sys_multi_clock_gettime32' [-Wframe-larger-than]
    1460 | SYSCALL_DEFINE1(multi_clock_gettime32, struct __ptp_multi_clock_get32 __user *, ptp_multi_clk_get)
         | ^
   include/linux/syscalls.h:219:36: note: expanded from macro 'SYSCALL_DEFINE1'
     219 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
         |                                    ^
   include/linux/syscalls.h:230:2: note: expanded from macro 'SYSCALL_DEFINEx'
     230 |         __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
         |         ^
   include/linux/syscalls.h:249:18: note: expanded from macro '__SYSCALL_DEFINEx'
     249 |         asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))  \
         |                         ^
   <scratch space>:147:1: note: expanded from here
     147 | __se_sys_multi_clock_gettime32
         | ^
   14 warnings generated.

vim +/__se_sys_multi_clock_gettime +1429 kernel/time/posix-timers.c

  1428	
> 1429	SYSCALL_DEFINE1(multi_clock_gettime, struct __ptp_multi_clock_get __user *, ptp_multi_clk_get)
  1430	{
  1431		const struct k_clock *kc;
  1432		struct timespec64 kernel_tp;
  1433		struct __ptp_multi_clock_get multi_clk_get;
  1434		int error;
  1435		unsigned int i, j;
  1436	
  1437		if (copy_from_user(&multi_clk_get, ptp_multi_clk_get, sizeof(multi_clk_get)))
  1438			return -EFAULT;
  1439	
  1440		if (multi_clk_get.n_samples > MULTI_PTP_MAX_SAMPLES)
  1441			return -EINVAL;
  1442		if (multi_clk_get.n_clocks > MULTI_PTP_MAX_CLOCKS)
  1443			return -EINVAL;
  1444	
  1445		for (j = 0; j < multi_clk_get.n_samples; j++) {
  1446			for (i = 0; i < multi_clk_get.n_clocks; i++) {
  1447				kc = clockid_to_kclock(multi_clk_get.clkid_arr[i]);
  1448				if (!kc)
  1449					return -EINVAL;
  1450				error = kc->clock_get_timespec(multi_clk_get.clkid_arr[i], &kernel_tp);
  1451				if (!error && put_timespec64(&kernel_tp, (struct __kernel_timespec __user *)
  1452							     &ptp_multi_clk_get->ts[j][i]))
  1453					error = -EFAULT;
  1454			}
  1455		}
  1456	
  1457		return error;
  1458	}
  1459	
> 1460	SYSCALL_DEFINE1(multi_clock_gettime32, struct __ptp_multi_clock_get32 __user *, ptp_multi_clk_get)
  1461	{
  1462		const struct k_clock *kc;
  1463		struct timespec64 kernel_tp;
  1464		struct __ptp_multi_clock_get multi_clk_get;
  1465		int error;
  1466		unsigned int i, j;
  1467	
  1468		if (copy_from_user(&multi_clk_get, ptp_multi_clk_get, sizeof(multi_clk_get)))
  1469			return -EFAULT;
  1470	
  1471		if (multi_clk_get.n_samples > MULTI_PTP_MAX_SAMPLES)
  1472			return -EINVAL;
  1473		if (multi_clk_get.n_clocks > MULTI_PTP_MAX_CLOCKS)
  1474			return -EINVAL;
  1475	
  1476		for (j = 0; j < multi_clk_get.n_samples; j++) {
  1477			for (i = 0; i < multi_clk_get.n_clocks; i++) {
  1478				kc = clockid_to_kclock(multi_clk_get.clkid_arr[i]);
  1479				if (!kc)
  1480					return -EINVAL;
  1481				error = kc->clock_get_timespec(multi_clk_get.clkid_arr[i], &kernel_tp);
  1482				if (!error && put_old_timespec32(&kernel_tp, (struct old_timespec32 __user *)
  1483								&ptp_multi_clk_get->ts[j][i]))
  1484					error = -EFAULT;
  1485			}
  1486		}
  1487	
  1488		return error;
  1489	}
  1490	

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