kernel: Fix stack randomization for the main thread #24467
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On architectures with custom swap to main the main thread is not being randomized properly. The size of the randomized stack created with z_setup_new_thread is being ignored and they are using the original main stack size. Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
andrewboie
approved these changes
Apr 17, 2020
ioannisg
reviewed
Apr 24, 2020
| { | ||
| #ifdef CONFIG_ARCH_HAS_CUSTOM_SWAP_TO_MAIN | ||
| arch_switch_to_main_thread(&z_main_thread, z_main_stack, | ||
| K_THREAD_STACK_SIZEOF(z_main_stack), | ||
| stack_size, |
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I think K_THREAD_STACK_SIZEOF was here to not allow passing the whole z_main_stack size, and remove the guard if needed.
| NULL, NULL, NULL, | ||
| CONFIG_MAIN_THREAD_PRIORITY, K_ESSENTIAL, "main"); | ||
| ret = z_setup_new_thread(&z_main_thread, z_main_stack, | ||
| CONFIG_MAIN_STACK_SIZE, bg_thread_main, |
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If i understand this correctly, this does not account for the guard area that in some cases is part of the thread stack memory allocation. Before this was not a problem because switch_to_main_thread was using the K_THREAD_STACK_SIZE_OF macro function, but now this is changed.
/*
* Note:
* The caller must guarantee that the stack_size passed here corresponds
* to the amount of stack memory available for the thread.
*/
void z_setup_new_thread(struct k_thread *new_thread,
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you are right, the guard is not being accounted. Will close this pr, since @andrew is addressing it in a different pr though.
andrewboie
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Jul 30, 2020
This now takes a stack pointer as an argument with TLS and random offsets accounted for properly. Based on zephyrproject-rtos#24467 authored by Flavio Ceolin. Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
nashif
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that referenced
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Jul 31, 2020
This now takes a stack pointer as an argument with TLS and random offsets accounted for properly. Based on #24467 authored by Flavio Ceolin. Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
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On architectures with custom swap to main the main thread is not being
randomized properly. The size of the randomized stack created with
z_setup_new_threadis being ignored and they are using the originalmain stack size.
Fixes: #23702