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Guarded the stack analyze binary search against a highest stack pointer that is not above the start of the stack, so a stack overflow or a corrupted control block no longer hangs or crashes the caller #727

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Guarded the stack analyze binary search against a highest stack pointer that is not above the start of the stack, so a stack overflow or a corrupted control block no longer hangs or crashes the caller #727

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13 changes: 10 additions & 3 deletions common/src/tx_thread_stack_analyze.c
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,7 @@ ULONG *stack_ptr;
ULONG *stack_lowest;
ULONG *stack_highest;
ULONG *probe_ptr;
ULONG *stack_limit;
ULONG probe_count;
UINT fill_present;
ULONG size;
Expand All @@ -99,10 +100,16 @@ ULONG size;
/* Pickup the highest stack pointer. */
stack_highest = TX_VOID_TO_ULONG_POINTER_CONVERT(thread_ptr -> tx_thread_stack_highest_ptr);

/* Determine if the pointer is null. */
if (stack_highest != TX_NULL)
/* Determine if the pointer is null or if the highest stack pointer is not above the
start of the stack. The latter indicates a stack overflow or a corrupted thread
control block, and the unsigned pointer arithmetic in the binary search below would
wrap around and never converge, hanging the caller. */
if ((stack_highest != TX_NULL) && (stack_highest > stack_lowest))
{

/* Remember the upper bound of the search so the scan below cannot run past it. */
stack_limit = stack_highest;

/* Restore interrupts. */
TX_RESTORE

Expand Down Expand Up @@ -173,7 +180,7 @@ ULONG size;
} while(size > ((ULONG) 1));

/* Position to first used word - at this point we are within a few words. */
while (*stack_ptr == TX_STACK_FILL)
while ((stack_ptr < stack_limit) && (*stack_ptr == TX_STACK_FILL))
{

/* Position to next word in stack. */
Expand Down
13 changes: 10 additions & 3 deletions common_smp/src/tx_thread_stack_analyze.c
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,7 @@ ULONG *stack_ptr;
ULONG *stack_lowest;
ULONG *stack_highest;
ULONG *probe_ptr;
ULONG *stack_limit;
ULONG probe_count;
UINT fill_present;
ULONG size;
Expand All @@ -99,10 +100,16 @@ ULONG size;
/* Pickup the highest stack pointer. */
stack_highest = TX_VOID_TO_ULONG_POINTER_CONVERT(thread_ptr -> tx_thread_stack_highest_ptr);

/* Determine if the pointer is null. */
if (stack_highest != TX_NULL)
/* Determine if the pointer is null or if the highest stack pointer is not above the
start of the stack. The latter indicates a stack overflow or a corrupted thread
control block, and the unsigned pointer arithmetic in the binary search below would
wrap around and never converge, hanging the caller. */
if ((stack_highest != TX_NULL) && (stack_highest > stack_lowest))
{

/* Remember the upper bound of the search so the scan below cannot run past it. */
stack_limit = stack_highest;

/* Restore interrupts. */
TX_RESTORE

Expand Down Expand Up @@ -173,7 +180,7 @@ ULONG size;
} while(size > ((ULONG) 1));

/* Position to first used word - at this point we are within a few words. */
while (*stack_ptr == TX_STACK_FILL)
while ((stack_ptr < stack_limit) && (*stack_ptr == TX_STACK_FILL))
{

/* Position to next word in stack. */
Expand Down
15 changes: 15 additions & 0 deletions test/smp/regression/threadx_thread_stack_checking_test.c
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Expand Up @@ -9,6 +9,8 @@
/* SPDX-License-Identifier: MIT */
/***************************************************************************/

// Some portions generated by Copilot (Opus 5).

/* This test is for the thread stack checking services. */

#include <stdio.h>
Expand Down Expand Up @@ -200,6 +202,19 @@ TX_THREAD fake_thread;
fake_thread.tx_thread_stack_highest_ptr = TX_NULL;
_tx_thread_stack_analyze(&fake_thread);

/* Call the stack analyze with a highest stack pointer below the start of the stack, which is
what a stack overflow or a corrupted control block looks like. This used to hang. */
fake_thread.tx_thread_id = ((ULONG) 0x54485244);
fake_thread.tx_thread_stack_start = (void *) 0x2000;
fake_thread.tx_thread_stack_highest_ptr = (void *) 0x1000;
_tx_thread_stack_analyze(&fake_thread);

/* Call the stack analyze with a highest stack pointer equal to the start of the stack. */
fake_thread.tx_thread_id = ((ULONG) 0x54485244);
fake_thread.tx_thread_stack_start = (void *) 0x2000;
fake_thread.tx_thread_stack_highest_ptr = (void *) 0x2000;
_tx_thread_stack_analyze(&fake_thread);

/* Clear the pattern in thread 2's stack. */
TX_MEMSET(thread_2_stack_start, (CHAR) 0x11, TEST_STACK_SIZE_PRINTF);

Expand Down
15 changes: 15 additions & 0 deletions test/tx/regression/threadx_thread_stack_checking_test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@
/* SPDX-License-Identifier: MIT */
/***************************************************************************/

// Some portions generated by Copilot (Opus 5).

/* This test is for the thread stack checking services. */

#include <stdio.h>
Expand Down Expand Up @@ -200,6 +202,19 @@ TX_THREAD fake_thread;
fake_thread.tx_thread_stack_highest_ptr = TX_NULL;
_tx_thread_stack_analyze(&fake_thread);

/* Call the stack analyze with a highest stack pointer below the start of the stack, which is
what a stack overflow or a corrupted control block looks like. This used to hang. */
fake_thread.tx_thread_id = ((ULONG) 0x54485244);
fake_thread.tx_thread_stack_start = (void *) 0x2000;
fake_thread.tx_thread_stack_highest_ptr = (void *) 0x1000;
_tx_thread_stack_analyze(&fake_thread);

/* Call the stack analyze with a highest stack pointer equal to the start of the stack. */
fake_thread.tx_thread_id = ((ULONG) 0x54485244);
fake_thread.tx_thread_stack_start = (void *) 0x2000;
fake_thread.tx_thread_stack_highest_ptr = (void *) 0x2000;
_tx_thread_stack_analyze(&fake_thread);

/* Clear the pattern in thread 2's stack. */
TX_MEMSET(thread_2_stack_start, (CHAR) 0x11, TEST_STACK_SIZE_PRINTF);

Expand Down
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