From: Al Viro <viro@zeniv.linux.org.uk>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: cluster-devel <cluster-devel@redhat.com>,
"Luck, Tony" <tony.luck@intel.com>, Jan Kara <jack@suse.cz>,
Andreas Gruenbacher <agruenba@redhat.com>,
x86@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Borislav Petkov <bp@alien8.de>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
ocfs2-devel@oss.oracle.com
Subject: Re: [Ocfs2-devel] [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter_writeable
Date: Sat, 28 Aug 2021 22:51:09 +0000 [thread overview]
Message-ID: <YSq93XetyaUuAsY7@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <YSq2WJindB0pJPRb@zeniv-ca.linux.org.uk>
On Sat, Aug 28, 2021 at 10:19:04PM +0000, Al Viro wrote:
> How about taking __clear_user() out of copy_fpregs_to_sigframe()
> and replacing the call of fault_in_pages_writeable() with
> if (!clear_user(buf_fx, fpu_user_xstate_size))
> goto retry;
> return -EFAULT;
> in the caller?
Something like this (completely untested)
Lift __clear_user() out of copy_fpregs_to_sigframe(), do not confuse EFAULT with
X86_TRAP_PF, don't bother with fault_in_pages_writeable() (pointless, since now
__clear_user() on error is not under pagefault_disable()). And don't bother
with retries on anything other than #PF...
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 5a18694a89b2..71c6621a262f 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -17,6 +17,7 @@
#include <linux/mm.h>
#include <asm/user.h>
+#include <asm/trapnr.h>
#include <asm/fpu/api.h>
#include <asm/fpu/xstate.h>
#include <asm/fpu/xcr.h>
@@ -345,7 +346,7 @@ static inline int xsave_to_user_sigframe(struct xregs_state __user *buf)
*/
err = __clear_user(&buf->header, sizeof(buf->header));
if (unlikely(err))
- return -EFAULT;
+ return -X86_TRAP_PF;
stac();
XSTATE_OP(XSAVE, buf, lmask, hmask, err);
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 445c57c9c539..611b9ed9c06b 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -135,18 +135,12 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
{
- int err;
-
if (use_xsave())
- err = xsave_to_user_sigframe(buf);
- else if (use_fxsr())
- err = fxsave_to_user_sigframe((struct fxregs_state __user *) buf);
+ return xsave_to_user_sigframe(buf);
+ if (use_fxsr())
+ return fxsave_to_user_sigframe((struct fxregs_state __user *) buf);
else
- err = fnsave_to_user_sigframe((struct fregs_state __user *) buf);
-
- if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size))
- err = -EFAULT;
- return err;
+ return fnsave_to_user_sigframe((struct fregs_state __user *) buf);
}
/*
@@ -205,9 +199,10 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
fpregs_unlock();
if (ret) {
- if (!fault_in_pages_writeable(buf_fx, fpu_user_xstate_size))
+ if (!__clear_user(buf_fx, fpu_user_xstate_size) &&
+ ret == -X86_TRAP_PF)
goto retry;
- return -EFAULT;
+ return -1;
}
/* Save the fsave header for the 32-bit frames. */
@@ -275,7 +270,7 @@ static int restore_fpregs_from_user(void __user *buf, u64 xrestore,
fpregs_unlock();
/* Try to handle #PF, but anything else is fatal. */
- if (ret != -EFAULT)
+ if (ret != -X86_TRAP_PF)
return -EINVAL;
ret = fault_in_pages_readable(buf, size);
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next prev parent reply other threads:[~2021-08-28 22:51 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-27 16:49 [Ocfs2-devel] [PATCH v7 00/19] gfs2: Fix mmap + page fault deadlocks Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 01/19] iov_iter: Fix iov_iter_get_pages{, _alloc} page fault return value Andreas Gruenbacher
2021-09-09 11:09 ` Christoph Hellwig
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 02/19] powerpc/kvm: Fix kvm_use_magic_page Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 03/19] gup: Turn fault_in_pages_{readable, writeable} into fault_in_{readable, writeable} Andreas Gruenbacher
2021-08-27 19:08 ` Al Viro
2021-09-03 14:56 ` Filipe Manana
2021-09-28 15:02 ` Andreas Gruenbacher
2021-09-28 16:37 ` Matthew Wilcox
2021-09-28 20:41 ` Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 04/19] iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable Andreas Gruenbacher
2021-08-27 18:53 ` Al Viro
2021-08-27 18:57 ` Linus Torvalds
2021-08-27 19:16 ` Al Viro
2021-08-27 20:56 ` Kari Argillander
2021-08-28 17:13 ` Linus Torvalds
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter_writeable Andreas Gruenbacher
2021-08-27 18:49 ` Al Viro
2021-08-27 19:05 ` Linus Torvalds
2021-08-27 19:23 ` Al Viro
2021-08-27 19:33 ` Linus Torvalds
2021-08-27 19:37 ` Al Viro
2021-08-27 21:48 ` Al Viro
2021-08-27 21:57 ` Al Viro
2021-08-27 23:22 ` Luck, Tony
2021-08-28 2:20 ` Luck, Tony
2021-08-28 21:47 ` Thomas Gleixner
2021-08-28 22:04 ` Al Viro
2021-08-28 22:11 ` Al Viro
2021-08-28 22:19 ` Al Viro
2021-08-28 22:51 ` Al Viro [this message]
2021-08-29 18:44 ` Thomas Gleixner
2021-08-29 19:46 ` Al Viro
2021-08-29 19:51 ` Thomas Gleixner
2021-08-28 22:20 ` Tony Luck
2021-08-29 1:40 ` Matthew Wilcox
2021-08-30 15:41 ` Luck, Tony
2021-08-28 22:23 ` Thomas Gleixner
2021-08-28 19:28 ` [Ocfs2-devel] [RFC][arm64] possible infinite loop in btrfs search_ioctl() Al Viro
2021-08-31 13:54 ` Catalin Marinas
2021-08-31 15:28 ` Al Viro
2021-08-31 16:01 ` Catalin Marinas
2021-10-11 17:37 ` Catalin Marinas
2021-10-11 19:15 ` Linus Torvalds
2021-10-11 21:08 ` Catalin Marinas
2021-10-11 23:59 ` Linus Torvalds
2021-10-12 17:27 ` Catalin Marinas
2021-10-12 17:58 ` Linus Torvalds
2021-10-18 17:13 ` Catalin Marinas
2021-10-21 0:46 ` Andreas Gruenbacher
2021-10-21 10:05 ` Catalin Marinas
2021-10-21 14:42 ` Andreas Gruenbacher
2021-10-21 17:09 ` Catalin Marinas
2021-10-21 18:00 ` Andreas Gruenbacher
2021-10-22 18:41 ` Catalin Marinas
2021-10-25 19:37 ` Andreas Gruenbacher
2021-10-22 2:30 ` Linus Torvalds
2021-10-22 9:34 ` Catalin Marinas
2021-08-29 0:58 ` [Ocfs2-devel] [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter_writeable Al Viro
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 06/19] gfs2: Add wrapper for iomap_file_buffered_write Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 07/19] gfs2: Clean up function may_grant Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 08/19] gfs2: Eliminate vestigial HIF_FIRST Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 09/19] gfs2: Remove redundant check from gfs2_glock_dq Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 10/19] gfs2: Introduce flag for glock holder auto-demotion Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 11/19] gfs2: Move the inode glock locking to gfs2_file_buffered_write Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 12/19] gfs2: Eliminate ip->i_gh Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 13/19] gfs2: Fix mmap + page fault deadlocks for buffered I/O Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 14/19] iomap: Fix iomap_dio_rw return value for user copies Andreas Gruenbacher
2021-09-03 18:54 ` Darrick J. Wong
2021-09-09 11:17 ` Christoph Hellwig
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 15/19] iomap: Support partial direct I/O on user copy failures Andreas Gruenbacher
2021-09-03 18:54 ` Darrick J. Wong
2021-09-09 11:20 ` Christoph Hellwig
2021-09-28 15:05 ` Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 16/19] iomap: Add done_before argument to iomap_dio_rw Andreas Gruenbacher
2021-08-27 18:30 ` Darrick J. Wong
2021-08-27 20:15 ` Andreas Gruenbacher
2021-08-27 21:32 ` Darrick J. Wong
2021-08-27 21:49 ` Andreas Grünbacher
2021-08-27 22:35 ` Linus Torvalds
2021-09-03 18:47 ` Darrick J. Wong
2021-09-03 18:53 ` Darrick J. Wong
2021-09-09 11:30 ` Christoph Hellwig
2021-09-09 17:22 ` Linus Torvalds
2021-09-10 7:36 ` Christoph Hellwig
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 17/19] gup: Introduce FOLL_NOFAULT flag to disable page faults Andreas Gruenbacher
2021-09-09 11:36 ` Christoph Hellwig
2021-09-09 17:17 ` Linus Torvalds
2021-09-10 7:24 ` Christoph Hellwig
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 18/19] iov_iter: Introduce nofault " Andreas Gruenbacher
2021-08-27 18:47 ` Al Viro
2021-08-27 19:56 ` Andreas Gruenbacher
2021-08-27 16:49 ` [Ocfs2-devel] [PATCH v7 19/19] gfs2: Fix mmap + page fault deadlocks for direct I/O Andreas Gruenbacher
2021-08-27 17:16 ` [Ocfs2-devel] [PATCH v7 00/19] gfs2: Fix mmap + page fault deadlocks Linus Torvalds
2021-09-01 19:52 ` Andreas Gruenbacher
2021-09-03 15:52 ` Linus Torvalds
2021-09-03 18:25 ` Al Viro
2021-09-03 18:47 ` Linus Torvalds
2021-09-03 19:51 ` Andreas Grünbacher
2021-09-03 15:07 ` Filipe Manana
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