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The recursive_loop() function is intended as a diagnostic to ensure that exhausting the stack is caught and mitigated. Currently, it uses pr_info() to ensure that the function has side effects that the compiler cannot simply optimize away, so that the stack footprint does not get reduced inadvertently. The typical mitigation for stack overflow is to kill the task, and this overflow may occur inside the call to pr_info(), which means it could be holding the console lock when this happens. This means that the console lock is never going to be released again, preventing the diagnostic prints related to the stack overflow handling from being visible on the console. So let's replace the call to pr_info() with a call to memzero_explicit(), which is not a 'magic' function name like memset() or memcpy(), which the compiler may replace with plain loads and stores. To ensure that the stack frames are nested rather than tail-called, put the call to memzero_explicit() after the recursive call. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20211007081235.382697-1-ardb@kernel.org |
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| .. | ||
| bugs.c | ||
| cfi.c | ||
| core.c | ||
| fortify.c | ||
| heap.c | ||
| lkdtm.h | ||
| Makefile | ||
| perms.c | ||
| powerpc.c | ||
| refcount.c | ||
| rodata.c | ||
| stackleak.c | ||
| usercopy.c | ||