From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 54E12493D2D; Tue, 15 Sep 2026 11:32:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789471952; cv=none; b=fRLxHlX6hJ2seVpTcjSmTxXFuH0V2MMYvKbJ56pzU+3VCYYg4Wn0n87tdNqtUhd8FYCCgFsoo5cGOeh6o6PaL8B11En45KI8jnARqfU0ssIRBQqW2i0hJAq2WIe4VC9r9knEkh/+icofE9BraH+dJmZaIc0XFZE4PUnymeF6uWw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789471952; c=relaxed/simple; bh=vs7iz3bKLJG7CXsTvZEBdGx9Li08YdT/8Wd/px3d4TY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=LDxwHgvm5ska4IJPHMfjyT6F12j2WrMFgBhEffPRMKbe6ERAqeSRqNBoVd2YwLehEDqR0NwnARUzKV2nCj+g2OavhR7k2fiSBTIiW6lvBV2D/HSTD6nKFR+qTDVLD6SOEZXrpwFS8XYy6gt0S3yGCDx404pOjtdg+QnSRHw+JhQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m+K2QXP/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="m+K2QXP/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A80221F000FF; Tue, 15 Sep 2026 11:32:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789471950; bh=i7wVyaLFDwSh4RsQ7x/yFwVaLvEj62at9uwFUzmPLMc=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=m+K2QXP/zbRGzsTYOiazh6maQXF3AuGZOI8kte5zBpS/uMcEZtnwlKYDvWPSx21mx 7TGqdB2C/asSsMklDxBThdjFd165iUvhBszGEb7vDKiAwqKwu88ALg4R3OQntDPmSy pL009b1opBUWgVeuBuk7lGh4yrLHaVwvTc34V6si7vaZd9pMcP+QTIh2EpkZPCrPHa roLy/D8FmA6vUFej8GssEIMuVEW8Xxbjc55QWU2ylDQo6Q1WZPwq27fmmdRMZbmLVP oJ72BLK/Gp1V/aWXjwbp1rJsiSD2B/wSlHgBuF1q53c4nr7kcTHLIyN7mofScYlI7c A/WVLIvzUUtlw== From: Christian Brauner Date: Tue, 15 Sep 2026 13:30:55 +0200 Subject: [PATCH RFC POC 09/50] m68k: commit fds on syscall exit Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260915-work-fd-reserve-unify-folded-v1-9-4d5217d6b246@kernel.org> References: <20260915-work-fd-reserve-unify-folded-v1-0-4d5217d6b246@kernel.org> In-Reply-To: <20260915-work-fd-reserve-unify-folded-v1-0-4d5217d6b246@kernel.org> To: Linus Torvalds Cc: Alexander Viro , Jann Horn , Jan Kara , Ingo Molnar , Peter Zijlstra , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Oleg Nesterov , linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, Jens Axboe , io-uring@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-gpio@vger.kernel.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, bpf@vger.kernel.org, David Airlie , virtualization@lists.linux.dev, kvm@vger.kernel.org, kexec@lists.infradead.org, linux-hyperv@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=openpgp-sha256; l=4471; i=brauner@kernel.org; h=from:subject:message-id; bh=vs7iz3bKLJG7CXsTvZEBdGx9Li08YdT/8Wd/px3d4TY=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSt1KnprokIqSkKVD/KZ/524Xdnh56o/lnaM35m5YhWv xThf2beUcrCIMbFICumyOLQbhIut5ynYrNRpgbMHFYmkCEMXJwCMJG4VkaGBu1Lkfsvr6ti2m+Q 0zx3V73WWh1tb5Pp3pZGNvef1XwNY2Q4/KqPv1PzYdm70LqORZH7stbOZDNYK+obXGf+cLdIFAc jAA== X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Add TIF_FD_SLOTS and test it on the untraced return from a system call in all three entry paths. A task that reserved descriptors calls syscall_trace_leave(), which commits them before the ptrace exit stop. The traced paths already end up there. Signed-off-by: Christian Brauner (Amutable) --- arch/m68k/68000/entry.S | 10 ++++++++++ arch/m68k/coldfire/entry.S | 12 ++++++++++++ arch/m68k/include/asm/thread_info.h | 2 ++ arch/m68k/kernel/entry.S | 2 ++ arch/m68k/kernel/ptrace.c | 3 +++ 5 files changed, 29 insertions(+) diff --git a/arch/m68k/68000/entry.S b/arch/m68k/68000/entry.S index c257cc415c47..479032af2f2f 100644 --- a/arch/m68k/68000/entry.S +++ b/arch/m68k/68000/entry.S @@ -89,6 +89,16 @@ ENTRY(system_call) jbsr %a0@ movel %d0,%sp@(PT_OFF_D0) /* save the return value*/ + /* descriptors reserved by the syscall are committed in syscall_trace_leave */ + getthreadinfo + btst #(TIF_FD_SLOTS%8),%a2@(TINFO_FLAGS+(31-TIF_FD_SLOTS)/8) + jeq ret_from_exception + subql #4,%sp /* dummy return address */ + SAVE_SWITCH_STACK + jbsr syscall_trace_leave + RESTORE_SWITCH_STACK + addql #4,%sp + ret_from_exception: btst #5,%sp@(PT_OFF_SR) /* check if returning to kernel*/ jeq Luser_return /* if so, skip resched, signals*/ diff --git a/arch/m68k/coldfire/entry.S b/arch/m68k/coldfire/entry.S index 4ea08336e2fb..43e47d4c0018 100644 --- a/arch/m68k/coldfire/entry.S +++ b/arch/m68k/coldfire/entry.S @@ -78,6 +78,18 @@ ENTRY(system_call) movel %d3,%a0 jbsr %a0@ movel %d0,%sp@(PT_OFF_D0) /* save the return value */ + + /* descriptors reserved by the syscall are committed in syscall_trace_leave */ + movel %sp,%d2 /* get thread_info pointer */ + andl #-THREAD_SIZE,%d2 /* at start of kernel stack */ + movel %d2,%a0 + btst #(TIF_FD_SLOTS%8),%a0@(TINFO_FLAGS+(31-TIF_FD_SLOTS)/8) + jeq ret_from_exception + subql #4,%sp /* dummy return address */ + SAVE_SWITCH_STACK + jbsr syscall_trace_leave + RESTORE_SWITCH_STACK + addql #4,%sp jra ret_from_exception 1: movel #-ENOSYS,%d2 /* strace needs -ENOSYS in PT_OFF_D0 */ diff --git a/arch/m68k/include/asm/thread_info.h b/arch/m68k/include/asm/thread_info.h index 5cb3ace55622..861b6f523bda 100644 --- a/arch/m68k/include/asm/thread_info.h +++ b/arch/m68k/include/asm/thread_info.h @@ -62,6 +62,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_NOTIFY_RESUME 5 /* callback before returning to user */ #define TIF_SIGPENDING 6 /* signal pending */ #define TIF_NEED_RESCHED 7 /* rescheduling necessary */ +#define TIF_FD_SLOTS 12 /* syscall prepared descriptors */ #define TIF_SECCOMP 13 /* seccomp syscall filtering active */ #define TIF_DELAYED_TRACE 14 /* single step a syscall */ #define TIF_SYSCALL_TRACE 15 /* syscall trace active */ @@ -71,6 +72,7 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) +#define _TIF_FD_SLOTS (1 << TIF_FD_SLOTS) #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_DELAYED_TRACE (1 << TIF_DELAYED_TRACE) #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S index 338b474910f7..9e4471f68165 100644 --- a/arch/m68k/kernel/entry.S +++ b/arch/m68k/kernel/entry.S @@ -229,6 +229,8 @@ ret_from_syscall: syscall_exit_work: btst #5,%sp@(PT_OFF_SR) | check if returning to kernel bnes 1b | if so, skip resched, signals + btst #4,%a1@(TINFO_FLAGS+2) | TIF_FD_SLOTS: commit descriptors + jne do_trace_exit lslw #1,%d0 jcs do_trace_exit jmi do_delayed_trace diff --git a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c index 4575f6487a9a..07103e6ddeb0 100644 --- a/arch/m68k/kernel/ptrace.c +++ b/arch/m68k/kernel/ptrace.c @@ -11,6 +11,7 @@ */ #include +#include #include #include #include @@ -289,6 +290,8 @@ asmlinkage int syscall_trace_enter(void) asmlinkage void syscall_trace_leave(void) { + if (test_thread_flag(TIF_FD_SLOTS)) + fd_slots_commit(task_pt_regs(current)); if (test_thread_flag(TIF_SYSCALL_TRACE)) ptrace_report_syscall_exit(task_pt_regs(current), 0); } -- 2.53.0