From 5b24ac2dfd3eb3e36f794af3aa7f2828b19035bd Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Thu, 22 Dec 2022 23:28:21 -0800 Subject: [PATCH 1/2] kcsan: test: don't put the expect array on the stack Size of the 'expect' array in the __report_matches is 1536 bytes, which is exactly the default frame size warning limit of the xtensa architecture. As a result allmodconfig xtensa kernel builds with the gcc that does not support the compiler plugins (which otherwise would push the said warning limit to 2K) fail with the following message: kernel/kcsan/kcsan_test.c:257:1: error: the frame size of 1680 bytes is larger than 1536 bytes Fix it by dynamically allocating the 'expect' array. Signed-off-by: Max Filippov Reviewed-by: Marco Elver Tested-by: Marco Elver --- kernel/kcsan/kcsan_test.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c index dcec1b743c69..a60c561724be 100644 --- a/kernel/kcsan/kcsan_test.c +++ b/kernel/kcsan/kcsan_test.c @@ -159,7 +159,7 @@ static bool __report_matches(const struct expect_report *r) const bool is_assert = (r->access[0].type | r->access[1].type) & KCSAN_ACCESS_ASSERT; bool ret = false; unsigned long flags; - typeof(observed.lines) expect; + typeof(*observed.lines) *expect; const char *end; char *cur; int i; @@ -168,6 +168,10 @@ static bool __report_matches(const struct expect_report *r) if (!report_available()) return false; + expect = kmalloc(sizeof(observed.lines), GFP_KERNEL); + if (WARN_ON(!expect)) + return false; + /* Generate expected report contents. */ /* Title */ @@ -253,6 +257,7 @@ static bool __report_matches(const struct expect_report *r) strstr(observed.lines[2], expect[1]))); out: spin_unlock_irqrestore(&observed.lock, flags); + kfree(expect); return ret; } From 4414c1f5c7a375eaa108676a56e12cc8234eb647 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Fri, 6 Jan 2023 23:30:57 -0800 Subject: [PATCH 2/2] xtensa: drop unused members of struct thread_struct bad_vaddr, bad_uaddr and error_code fields are set but never read by the xtensa arch-specific code. Drop them. Also drop the commented out info field. Signed-off-by: Max Filippov --- arch/xtensa/include/asm/processor.h | 9 --------- arch/xtensa/kernel/traps.c | 2 -- arch/xtensa/mm/fault.c | 4 ---- 3 files changed, 15 deletions(-) diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index 228e4dff5fb2..a6d09fe04831 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -154,11 +154,6 @@ struct thread_struct { unsigned long ra; /* kernel's a0: return address and window call size */ unsigned long sp; /* kernel's a1: stack pointer */ - /* struct xtensa_cpuinfo info; */ - - unsigned long bad_vaddr; /* last user fault */ - unsigned long bad_uaddr; /* last kernel fault accessing user space */ - unsigned long error_code; #ifdef CONFIG_HAVE_HW_BREAKPOINT struct perf_event *ptrace_bp[XCHAL_NUM_IBREAK]; struct perf_event *ptrace_wp[XCHAL_NUM_DBREAK]; @@ -176,10 +171,6 @@ struct thread_struct { { \ ra: 0, \ sp: sizeof(init_stack) + (long) &init_stack, \ - /*info: {0}, */ \ - bad_vaddr: 0, \ - bad_uaddr: 0, \ - error_code: 0, \ } diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index 0c25e035ff10..cd98366a9b23 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -362,8 +362,6 @@ static void do_unaligned_user(struct pt_regs *regs) __die_if_kernel("Unhandled unaligned exception in kernel", regs, SIGKILL); - current->thread.bad_vaddr = regs->excvaddr; - current->thread.error_code = -3; pr_info_ratelimited("Unaligned memory access to %08lx in '%s' " "(pid = %d, pc = %#010lx)\n", regs->excvaddr, current->comm, diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c index 8c781b05c0bd..faf7cf35a0ee 100644 --- a/arch/xtensa/mm/fault.c +++ b/arch/xtensa/mm/fault.c @@ -206,8 +206,6 @@ good_area: bad_area: mmap_read_unlock(mm); if (user_mode(regs)) { - current->thread.bad_vaddr = address; - current->thread.error_code = is_write; force_sig_fault(SIGSEGV, code, (void *) address); return; } @@ -232,7 +230,6 @@ do_sigbus: /* Send a sigbus, regardless of whether we were in kernel * or user mode. */ - current->thread.bad_vaddr = address; force_sig_fault(SIGBUS, BUS_ADRERR, (void *) address); /* Kernel mode? Handle exceptions or die */ @@ -252,7 +249,6 @@ bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) if ((entry = search_exception_tables(regs->pc)) != NULL) { pr_debug("%s: Exception at pc=%#010lx (%lx)\n", current->comm, regs->pc, entry->fixup); - current->thread.bad_uaddr = address; regs->pc = entry->fixup; return; }