diff options
| -rw-r--r-- | Kernel/Thread.cpp | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/Kernel/Thread.cpp b/Kernel/Thread.cpp index 059914338a..fa58eae54a 100644 --- a/Kernel/Thread.cpp +++ b/Kernel/Thread.cpp @@ -932,11 +932,11 @@ DispatchSignalResult Thread::dispatch_signal(u8 signal) #if ARCH(I386) // Align the stack to 16 bytes. - // Note that we push 56 bytes (4 * 14) on to the stack, - // so we need to account for this here. - // 56 % 16 = 8, so we only need to take 8 bytes into consideration for + // Note that we push 52 bytes (4 * 13) on to the stack + // before the return address, so we need to account for this here. + // 56 % 16 = 4, so we only need to take 4 bytes into consideration for // the stack alignment. - FlatPtr stack_alignment = (stack - 8) % 16; + FlatPtr stack_alignment = (stack - 4) % 16; stack -= stack_alignment; push_value_on_user_stack(stack, ret_flags); @@ -952,12 +952,12 @@ DispatchSignalResult Thread::dispatch_signal(u8 signal) push_value_on_user_stack(stack, state.edi); #else // Align the stack to 16 bytes. - // Note that we push 176 bytes (8 * 22) on to the stack, - // so we need to account for this here. - // 22 % 2 = 0, so we dont need to take anything into consideration - // for the alignment. + // Note that we push 168 bytes (8 * 21) on to the stack + // before the return address, so we need to account for this here. + // 168 % 16 = 8, so we only need to take 8 bytes into consideration for + // the stack alignment. // We also are not allowed to touch the thread's red-zone of 128 bytes - FlatPtr stack_alignment = stack % 16; + FlatPtr stack_alignment = (stack - 8) % 16; stack -= 128 + stack_alignment; push_value_on_user_stack(stack, ret_flags); @@ -986,13 +986,14 @@ DispatchSignalResult Thread::dispatch_signal(u8 signal) push_value_on_user_stack(stack, signal); push_value_on_user_stack(stack, handler_vaddr.get()); + + VERIFY((stack % 16) == 0); + push_value_on_user_stack(stack, 0); // push fake return address // We write back the adjusted stack value into the register state. // We have to do this because we can't just pass around a reference to a packed field, as it's UB. state.set_userspace_sp(stack); - - VERIFY((stack % 16) == 0); }; // We now place the thread state on the userspace stack. |