arch/riscv/kernel/signal.c:126 __restore_v_state() warn: maybe return -EFAULT instead of the bytes remaining?

arch/riscv/kernel/signal.c:126 __restore_v_state() warn: maybe return -EFAULT instead of the bytes remaining?

[kernel test robot]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: linux-kernel@vger.kernel.org
TO: Nathan Chancellor <nathan@kernel.org>
CC: Palmer Dabbelt <palmer@rivosinc.com>
CC: Andy Chiu <andybnac@gmail.com>
CC: Conor Dooley <conor.dooley@microchip.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   9b2ffa6148b1e4468d08f7e0e7e371c43cac9ffe
commit: 3aff0c459e77ac0fb1c4d6884433467f797f7357 RISC-V: Drop invalid test from CONFIG_AS_HAS_OPTION_ARCH
date:   10 months ago
:::::: branch date: 2 days ago
:::::: commit date: 10 months ago
config: riscv-randconfig-r073-20241225 (https://download.01.org/0day-ci/archive/20241226/202412261919.8WV3iSqf-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)

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/202412261919.8WV3iSqf-lkp@intel.com/

New smatch warnings:
arch/riscv/kernel/signal.c:126 __restore_v_state() warn: maybe return -EFAULT instead of the bytes remaining?

Old smatch warnings:
arch/riscv/kernel/signal.c:50 restore_fp_state() warn: maybe return -EFAULT instead of the bytes remaining?
arch/riscv/kernel/signal.c:64 save_fp_state() warn: maybe return -EFAULT instead of the bytes remaining?
arch/riscv/kernel/signal.c:138 __restore_v_state() warn: maybe return -EFAULT instead of the bytes remaining?
arch/riscv/kernel/signal.c:158 restore_sigcontext() warn: maybe return -EFAULT instead of the bytes remaining?

vim +126 arch/riscv/kernel/signal.c

8ee0b41898fa26f Greentime Hu 2023-06-05  110  
8ee0b41898fa26f Greentime Hu 2023-06-05  111  /*
8ee0b41898fa26f Greentime Hu 2023-06-05  112   * Restore Vector extension context from the user's signal frame. This function
8ee0b41898fa26f Greentime Hu 2023-06-05  113   * assumes a valid extension header. So magic and size checking must be done by
8ee0b41898fa26f Greentime Hu 2023-06-05  114   * the caller.
8ee0b41898fa26f Greentime Hu 2023-06-05  115   */
8ee0b41898fa26f Greentime Hu 2023-06-05  116  static long __restore_v_state(struct pt_regs *regs, void __user *sc_vec)
8ee0b41898fa26f Greentime Hu 2023-06-05  117  {
8ee0b41898fa26f Greentime Hu 2023-06-05  118  	long err;
8ee0b41898fa26f Greentime Hu 2023-06-05  119  	struct __sc_riscv_v_state __user *state = sc_vec;
8ee0b41898fa26f Greentime Hu 2023-06-05  120  	void __user *datap;
8ee0b41898fa26f Greentime Hu 2023-06-05  121  
8ee0b41898fa26f Greentime Hu 2023-06-05  122  	/* Copy everything of __sc_riscv_v_state except datap. */
8ee0b41898fa26f Greentime Hu 2023-06-05  123  	err = __copy_from_user(&current->thread.vstate, &state->v_state,
8ee0b41898fa26f Greentime Hu 2023-06-05  124  			       offsetof(struct __riscv_v_ext_state, datap));
8ee0b41898fa26f Greentime Hu 2023-06-05  125  	if (unlikely(err))
8ee0b41898fa26f Greentime Hu 2023-06-05 @126  		return err;
8ee0b41898fa26f Greentime Hu 2023-06-05  127  
8ee0b41898fa26f Greentime Hu 2023-06-05  128  	/* Copy the pointer datap itself. */
8ee0b41898fa26f Greentime Hu 2023-06-05  129  	err = __get_user(datap, &state->v_state.datap);
8ee0b41898fa26f Greentime Hu 2023-06-05  130  	if (unlikely(err))
8ee0b41898fa26f Greentime Hu 2023-06-05  131  		return err;
8ee0b41898fa26f Greentime Hu 2023-06-05  132  	/*
8ee0b41898fa26f Greentime Hu 2023-06-05  133  	 * Copy the whole vector content from user space datap. Use
8ee0b41898fa26f Greentime Hu 2023-06-05  134  	 * copy_from_user to prevent information leak.
8ee0b41898fa26f Greentime Hu 2023-06-05  135  	 */
8ee0b41898fa26f Greentime Hu 2023-06-05  136  	err = copy_from_user(current->thread.vstate.datap, datap, riscv_v_vsize);
8ee0b41898fa26f Greentime Hu 2023-06-05  137  	if (unlikely(err))
8ee0b41898fa26f Greentime Hu 2023-06-05  138  		return err;
8ee0b41898fa26f Greentime Hu 2023-06-05  139  
7df56cbc27e4239 Andy Chiu    2024-01-15  140  	riscv_v_vstate_set_restore(current, regs);
8ee0b41898fa26f Greentime Hu 2023-06-05  141  
8ee0b41898fa26f Greentime Hu 2023-06-05  142  	return err;
8ee0b41898fa26f Greentime Hu 2023-06-05  143  }
8ee0b41898fa26f Greentime Hu 2023-06-05  144  #else
8ee0b41898fa26f Greentime Hu 2023-06-05  145  #define save_v_state(task, regs) (0)
8ee0b41898fa26f Greentime Hu 2023-06-05  146  #define __restore_v_state(task, regs) (0)
8ee0b41898fa26f Greentime Hu 2023-06-05  147  #endif
8ee0b41898fa26f Greentime Hu 2023-06-05  148  

:::::: The code at line 126 was first introduced by commit
:::::: 8ee0b41898fa26f66e32237f179b6989c65600d6 riscv: signal: Add sigcontext save/restore for vector

:::::: TO: Greentime Hu <greentime.hu@sifive.com>
:::::: CC: Palmer Dabbelt <palmer@rivosinc.com>

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