From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Date: Fri, 18 Sep 2020 12:45:25 +0000 Subject: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-Id: <20200918124533.3487701-2-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <20200918124533.3487701-1-hch@lst.de> In-Reply-To: <20200918124533.3487701-1-hch@lst.de> To: Alexander Viro Cc: Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Add a flag to force processing a syscall as a compat syscall. This is required so that in_compat_syscall() works for I/O submitted by io_uring helper threads on behalf of compat syscalls. Signed-off-by: Christoph Hellwig --- arch/sparc/include/asm/compat.h | 3 ++- arch/x86/include/asm/compat.h | 2 +- fs/io_uring.c | 9 +++++++++ include/linux/compat.h | 5 ++++- include/linux/sched.h | 1 + 5 files changed, 17 insertions(+), 3 deletions(-) diff --git a/arch/sparc/include/asm/compat.h b/arch/sparc/include/asm/compat.h index 40a267b3bd5208..fee6c51d36e869 100644 --- a/arch/sparc/include/asm/compat.h +++ b/arch/sparc/include/asm/compat.h @@ -211,7 +211,8 @@ static inline int is_compat_task(void) static inline bool in_compat_syscall(void) { /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ - return pt_regs_trap_type(current_pt_regs()) = 0x110; + return pt_regs_trap_type(current_pt_regs()) = 0x110 || + (current->flags & PF_FORCE_COMPAT); } #define in_compat_syscall in_compat_syscall #endif diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h index d4edf281fff49d..fbab072d4e5b31 100644 --- a/arch/x86/include/asm/compat.h +++ b/arch/x86/include/asm/compat.h @@ -208,7 +208,7 @@ static inline bool in_32bit_syscall(void) #ifdef CONFIG_COMPAT static inline bool in_compat_syscall(void) { - return in_32bit_syscall(); + return in_32bit_syscall() || (current->flags & PF_FORCE_COMPAT); } #define in_compat_syscall in_compat_syscall /* override the generic impl */ #endif diff --git a/fs/io_uring.c b/fs/io_uring.c index 3790c7fe9fee22..5755d557c3f7bc 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5449,6 +5449,9 @@ static int io_req_defer_prep(struct io_kiocb *req, if (unlikely(ret)) return ret; + if (req->ctx->compat) + current->flags |= PF_FORCE_COMPAT; + switch (req->opcode) { case IORING_OP_NOP: break; @@ -5546,6 +5549,7 @@ static int io_req_defer_prep(struct io_kiocb *req, break; } + current->flags &= ~PF_FORCE_COMPAT; return ret; } @@ -5669,6 +5673,9 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_ring_ctx *ctx = req->ctx; int ret; + if (ctx->compat) + current->flags |= PF_FORCE_COMPAT; + switch (req->opcode) { case IORING_OP_NOP: ret = io_nop(req, cs); @@ -5898,6 +5905,8 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, break; } + current->flags &= ~PF_FORCE_COMPAT; + if (ret) return ret; diff --git a/include/linux/compat.h b/include/linux/compat.h index b354ce58966e2d..685066f7ad325f 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -891,7 +891,10 @@ asmlinkage long compat_sys_socketcall(int call, u32 __user *args); */ #ifndef in_compat_syscall -static inline bool in_compat_syscall(void) { return is_compat_task(); } +static inline bool in_compat_syscall(void) +{ + return is_compat_task() || (current->flags & PF_FORCE_COMPAT); +} #endif /** diff --git a/include/linux/sched.h b/include/linux/sched.h index afe01e232935fa..c8b183b5655a1e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1491,6 +1491,7 @@ extern struct pid *cad_pid; */ #define PF_IDLE 0x00000002 /* I am an IDLE thread */ #define PF_EXITING 0x00000004 /* Getting shut down */ +#define PF_FORCE_COMPAT 0x00000008 /* acting as compat task */ #define PF_VCPU 0x00000010 /* I'm a virtual CPU */ #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */ #define PF_FORKNOEXEC 0x00000040 /* Forked but didn't exec */ -- 2.28.0