xt-sys/exectos
xt-sys/exectos
3
5
Fork 3
Code Issues 3 Pull Requests 1 Actions Projects 1 Releases Wiki Activity

Fix race condition in HlComPortReadLsr
All checks were successful
Builds / ExectOS (amd64, debug) (push) Successful in 44s
Details
Builds / ExectOS (amd64, release) (push) Successful in 45s
Details
Builds / ExectOS (i686, release) (push) Successful in 43s
Details
Builds / ExectOS (i686, debug) (push) Successful in 46s
Details

Browse Source 
The static local variable RingFlag in HlComPortReadLsr caused shared state across multiple calls and ports, leading to race conditions and incorrect behavior.
This commit is contained in:
Aiken Harris 2025-08-06 09:01:47 +02:00 committed by CodingWorkshop Signing Team
parent 9badf36ce0
commit d7552f1dce
Signed by: CodingWorkshop Signing Team
GPG Key ID: 6DC88369C82795D2
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
xtoskrnl/hl/cport.c
View File

@ -165,7 +165,6 @@ HlComPortReadLsr(IN PCPPORT Port,
IN UCHAR Byte) IN UCHAR Byte)
{ {
UCHAR Lsr, Msr; UCHAR Lsr, Msr;
STATIC UCHAR RingFlag;
/* Read the Line Status Register (LSR) */ /* Read the Line Status Register (LSR) */
Lsr = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_LSR)); Lsr = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_LSR));
@ -175,8 +174,8 @@ HlComPortReadLsr(IN PCPPORT Port,
{ {
/* Check Modem Status Register (MSR) for ring indicator */ /* Check Modem Status Register (MSR) for ring indicator */
Msr = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_MSR)); Msr = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_MSR));
RingFlag |= (Msr & COMPORT_MSR_RI) ? 1 : 2; Port->Ring |= (Msr & COMPORT_MSR_RI) ? 1 : 2;
if(RingFlag == 3) if(Port->Ring == 3)
{ {
/* Ring indicator toggled, use modem control */ /* Ring indicator toggled, use modem control */
Port->Flags |= COMPORT_FLAG_MC; Port->Flags |= COMPORT_FLAG_MC;
@ -283,6 +282,7 @@ HlInitializeComPort(IN OUT PCPPORT Port,
Port->Address = PortAddress; Port->Address = PortAddress;
Port->Baud = BaudRate; Port->Baud = BaudRate;
Port->Flags = Flags; Port->Flags = Flags;
Port->Ring = 0;
/* Return success */ /* Return success */
return STATUS_SUCCESS; return STATUS_SUCCESS;