From c0c7fa4e7a512006710c8e4d6b6f7b40c9f786cd Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Tue, 10 Jun 2025 14:09:35 +0200 Subject: [PATCH 1/4] docs: arm64: Fix ICC_SRE_EL2 register typo in booting.rst Fix trivial ICC_SRE_EL2 register spelling typo in booting.rst. Signed-off-by: Lorenzo Pieralisi Cc: Jonathan Corbet Cc: Will Deacon CC: Catalin Marinas Link: https://lore.kernel.org/r/20250610120935.852034-1-lpieralisi@kernel.org Signed-off-by: Will Deacon --- Documentation/arch/arm64/booting.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/arch/arm64/booting.rst b/Documentation/arch/arm64/booting.rst index dee7b6de864f..ee9b790c0d72 100644 --- a/Documentation/arch/arm64/booting.rst +++ b/Documentation/arch/arm64/booting.rst @@ -234,7 +234,7 @@ Before jumping into the kernel, the following conditions must be met: - If the kernel is entered at EL1: - - ICC.SRE_EL2.Enable (bit 3) must be initialised to 0b1 + - ICC_SRE_EL2.Enable (bit 3) must be initialised to 0b1 - ICC_SRE_EL2.SRE (bit 0) must be initialised to 0b1. - The DT or ACPI tables must describe a GICv3 interrupt controller. From 650768c512faba8070bf4cfbb28c95eb5cd203f3 Mon Sep 17 00:00:00 2001 From: Dev Jain Date: Tue, 27 May 2025 13:56:33 +0530 Subject: [PATCH 2/4] arm64: Restrict pagetable teardown to avoid false warning Commit 9c006972c3fe ("arm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()") removes the pxd_present() checks because the caller checks pxd_present(). But, in case of vmap_try_huge_pud(), the caller only checks pud_present(); pud_free_pmd_page() recurses on each pmd through pmd_free_pte_page(), wherein the pmd may be none. Thus it is possible to hit a warning in the latter, since pmd_none => !pmd_table(). Thus, add a pmd_present() check in pud_free_pmd_page(). This problem was found by code inspection. Fixes: 9c006972c3fe ("arm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()") Cc: stable@vger.kernel.org Reported-by: Ryan Roberts Acked-by: David Hildenbrand Signed-off-by: Dev Jain Reviewed-by: Catalin Marinas Reviewed-by: Anshuman Khandual Reviewed-by: Ryan Roberts Link: https://lore.kernel.org/r/20250527082633.61073-1-dev.jain@arm.com Signed-off-by: Will Deacon --- arch/arm64/mm/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 8fcf59ba39db..00ab1d648db6 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1305,7 +1305,8 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) next = addr; end = addr + PUD_SIZE; do { - pmd_free_pte_page(pmdp, next); + if (pmd_present(pmdp_get(pmdp))) + pmd_free_pte_page(pmdp, next); } while (pmdp++, next += PMD_SIZE, next != end); pud_clear(pudp); From d2be3270f40b1330f8c1c9512c59dd085a758ac0 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Wed, 11 Jun 2025 17:28:13 +0100 Subject: [PATCH 3/4] arm64/gcs: Don't call gcs_free() during flush_gcs() Currently we call gcs_free() during flush_gcs() to reset the thread state for GCS. This includes unmapping any kernel allocated GCS, but this is redundant when doing a flush_thread() since we are reinitialising the thread memory too. Inline the reinitialisation of the thread struct. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20250611-arm64-gcs-flush-thread-v1-1-cc26feeddabd@kernel.org Signed-off-by: Will Deacon --- arch/arm64/kernel/process.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index a5ca15daeb8a..5954cec19660 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -288,7 +288,9 @@ static void flush_gcs(void) if (!system_supports_gcs()) return; - gcs_free(current); + current->thread.gcspr_el0 = 0; + current->thread.gcs_base = 0; + current->thread.gcs_size = 0; current->thread.gcs_el0_mode = 0; write_sysreg_s(GCSCRE0_EL1_nTR, SYS_GCSCRE0_EL1); write_sysreg_s(0, SYS_GCSPR_EL0); From 39dfc971e42d886e7df01371cd1bef505076d84c Mon Sep 17 00:00:00 2001 From: Tengda Wu Date: Wed, 4 Jun 2025 00:55:33 +0000 Subject: [PATCH 4/4] arm64/ptrace: Fix stack-out-of-bounds read in regs_get_kernel_stack_nth() KASAN reports a stack-out-of-bounds read in regs_get_kernel_stack_nth(). Call Trace: [ 97.283505] BUG: KASAN: stack-out-of-bounds in regs_get_kernel_stack_nth+0xa8/0xc8 [ 97.284677] Read of size 8 at addr ffff800089277c10 by task 1.sh/2550 [ 97.285732] [ 97.286067] CPU: 7 PID: 2550 Comm: 1.sh Not tainted 6.6.0+ #11 [ 97.287032] Hardware name: linux,dummy-virt (DT) [ 97.287815] Call trace: [ 97.288279] dump_backtrace+0xa0/0x128 [ 97.288946] show_stack+0x20/0x38 [ 97.289551] dump_stack_lvl+0x78/0xc8 [ 97.290203] print_address_description.constprop.0+0x84/0x3c8 [ 97.291159] print_report+0xb0/0x280 [ 97.291792] kasan_report+0x84/0xd0 [ 97.292421] __asan_load8+0x9c/0xc0 [ 97.293042] regs_get_kernel_stack_nth+0xa8/0xc8 [ 97.293835] process_fetch_insn+0x770/0xa30 [ 97.294562] kprobe_trace_func+0x254/0x3b0 [ 97.295271] kprobe_dispatcher+0x98/0xe0 [ 97.295955] kprobe_breakpoint_handler+0x1b0/0x210 [ 97.296774] call_break_hook+0xc4/0x100 [ 97.297451] brk_handler+0x24/0x78 [ 97.298073] do_debug_exception+0xac/0x178 [ 97.298785] el1_dbg+0x70/0x90 [ 97.299344] el1h_64_sync_handler+0xcc/0xe8 [ 97.300066] el1h_64_sync+0x78/0x80 [ 97.300699] kernel_clone+0x0/0x500 [ 97.301331] __arm64_sys_clone+0x70/0x90 [ 97.302084] invoke_syscall+0x68/0x198 [ 97.302746] el0_svc_common.constprop.0+0x11c/0x150 [ 97.303569] do_el0_svc+0x38/0x50 [ 97.304164] el0_svc+0x44/0x1d8 [ 97.304749] el0t_64_sync_handler+0x100/0x130 [ 97.305500] el0t_64_sync+0x188/0x190 [ 97.306151] [ 97.306475] The buggy address belongs to stack of task 1.sh/2550 [ 97.307461] and is located at offset 0 in frame: [ 97.308257] __se_sys_clone+0x0/0x138 [ 97.308910] [ 97.309241] This frame has 1 object: [ 97.309873] [48, 184) 'args' [ 97.309876] [ 97.310749] The buggy address belongs to the virtual mapping at [ 97.310749] [ffff800089270000, ffff800089279000) created by: [ 97.310749] dup_task_struct+0xc0/0x2e8 [ 97.313347] [ 97.313674] The buggy address belongs to the physical page: [ 97.314604] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14f69a [ 97.315885] flags: 0x15ffffe00000000(node=1|zone=2|lastcpupid=0xfffff) [ 97.316957] raw: 015ffffe00000000 0000000000000000 dead000000000122 0000000000000000 [ 97.318207] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 [ 97.319445] page dumped because: kasan: bad access detected [ 97.320371] [ 97.320694] Memory state around the buggy address: [ 97.321511] ffff800089277b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 97.322681] ffff800089277b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 97.323846] >ffff800089277c00: 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00 00 [ 97.325023] ^ [ 97.325683] ffff800089277c80: 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 f3 f3 [ 97.326856] ffff800089277d00: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 This issue seems to be related to the behavior of some gcc compilers and was also fixed on the s390 architecture before: commit d93a855c31b7 ("s390/ptrace: Avoid KASAN false positives in regs_get_kernel_stack_nth()") As described in that commit, regs_get_kernel_stack_nth() has confirmed that `addr` is on the stack, so reading the value at `*addr` should be allowed. Use READ_ONCE_NOCHECK() helper to silence the KASAN check for this case. Fixes: 0a8ea52c3eb1 ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature") Signed-off-by: Tengda Wu Link: https://lore.kernel.org/r/20250604005533.1278992-1-wutengda@huaweicloud.com [will: Use '*addr' as the argument to READ_ONCE_NOCHECK()] Signed-off-by: Will Deacon --- arch/arm64/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index a360e52db02f..ee94b72bf8fb 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -141,7 +141,7 @@ unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n) addr += n; if (regs_within_kernel_stack(regs, (unsigned long)addr)) - return *addr; + return READ_ONCE_NOCHECK(*addr); else return 0; }