6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nylon Chen nylon.chen@sifive.com
[ Upstream commit 61a74ad254628ccd9e88838c3c622885dfb6c588 ]
Use copy_from_user_nofault() and copy_to_user_nofault() instead of copy_from/to_user functions in the misaligned access trap handlers.
The following bug report was found when executing misaligned memory accesses:
BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:162 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 115, name: two preempt_count: 0, expected: 0 CPU: 0 UID: 0 PID: 115 Comm: two Not tainted 6.14.0-rc5 #24 Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff800160ea>] dump_backtrace+0x1c/0x24 [<ffffffff80002304>] show_stack+0x28/0x34 [<ffffffff80010fae>] dump_stack_lvl+0x4a/0x68 [<ffffffff80010fe0>] dump_stack+0x14/0x1c [<ffffffff8004e44e>] __might_resched+0xfa/0x104 [<ffffffff8004e496>] __might_sleep+0x3e/0x62 [<ffffffff801963c4>] __might_fault+0x1c/0x24 [<ffffffff80425352>] _copy_from_user+0x28/0xaa [<ffffffff8000296c>] handle_misaligned_store+0x204/0x254 [<ffffffff809eae82>] do_trap_store_misaligned+0x24/0xee [<ffffffff809f4f1a>] handle_exception+0x146/0x152
Fixes: b686ecdeacf6 ("riscv: misaligned: Restrict user access to kernel memory") Fixes: 441381506ba7 ("riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code")
Signed-off-by: Zong Li zong.li@sifive.com Signed-off-by: Nylon Chen nylon.chen@sifive.com Link: https://lore.kernel.org/r/20250411073850.3699180-3-nylon.chen@sifive.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/kernel/traps_misaligned.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index 77c788660223b..56f06a27d45fb 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -455,7 +455,7 @@ static int handle_scalar_misaligned_load(struct pt_regs *regs)
val.data_u64 = 0; if (user_mode(regs)) { - if (copy_from_user(&val, (u8 __user *)addr, len)) + if (copy_from_user_nofault(&val, (u8 __user *)addr, len)) return -1; } else { memcpy(&val, (u8 *)addr, len); @@ -556,7 +556,7 @@ static int handle_scalar_misaligned_store(struct pt_regs *regs) return -EOPNOTSUPP;
if (user_mode(regs)) { - if (copy_to_user((u8 __user *)addr, &val, len)) + if (copy_to_user_nofault((u8 __user *)addr, &val, len)) return -1; } else { memcpy((u8 *)addr, &val, len);