[PATCH RFC POC 06/50] arm64: commit fds on syscall exit
From: Christian Brauner <brauner@kernel.org>
Date: 2026-09-15 11:32:06
Also in:
bpf, dri-devel, io-uring, kexec, kvm, linux-alpha, linux-arm-kernel, linux-arm-msm, linux-fsdevel, linux-gpio, linux-hyperv, linux-m68k, linux-mips, linux-mm, linux-sh, linux-um, lkml, netdev, sparclinux, virtualization
Subsystem:
arm64 port (aarch64 architecture), ptrace support, the rest · Maintainers:
Catalin Marinas, Will Deacon, Oleg Nesterov, Linus Torvalds
Add TIF_FD_SLOTS to the syscall work bits. el0_svc_common() rereads the flags after the system call and takes the trace exit for any of them. So a task that reserved descriptors ends up in syscall_trace_exit() which commits them before audit and the ptrace exit stop. Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> --- arch/arm64/include/asm/thread_info.h | 4 +++- arch/arm64/kernel/ptrace.c | 4 ++++ 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 5d7fe3e153c8..e48006eb98a8 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h@@ -74,6 +74,7 @@ void arch_setup_new_exec(void); #define TIF_SECCOMP 11 /* syscall secure computing */ #define TIF_SYSCALL_EMU 12 /* syscall emulation active */ #define TIF_PATCH_PENDING 13 /* pending live patching update */ +#define TIF_FD_SLOTS 14 /* syscall prepared descriptors */ #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ #define TIF_FREEZE 19 #define TIF_RESTORE_SIGMASK 20
@@ -107,10 +108,11 @@ void arch_setup_new_exec(void); #define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) #define _TIF_TSC_SIGSEGV (1 << TIF_TSC_SIGSEGV) +#define _TIF_FD_SLOTS (1 << TIF_FD_SLOTS) #define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \ - _TIF_SYSCALL_EMU) + _TIF_SYSCALL_EMU | _TIF_FD_SLOTS) #ifdef CONFIG_SHADOW_CALL_STACK #define INIT_SCS \
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index f743cbec1c3a..3bedfed977d4 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c@@ -28,6 +28,7 @@ #include <linux/hw_breakpoint.h> #include <linux/regset.h> #include <linux/elf.h> +#include <linux/file.h> #include <linux/rseq.h> #include <asm/compat.h>
@@ -2486,6 +2487,9 @@ void syscall_trace_exit(struct pt_regs *regs) { unsigned long flags = read_thread_flags(); + if (flags & _TIF_FD_SLOTS) + fd_slots_commit(regs); + audit_syscall_exit(regs); if (flags & _TIF_SYSCALL_TRACEPOINT)
--
2.53.0