From: Willy Tarreau <w@1wt.eu>
To: Ben Hutchings <ben@decadent.org.uk>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Andi Kleen <andi@firstfloor.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [ 05/48] x86_64, switch_to(): Load TLS descriptors before switching DS and ES
Date: Fri, 15 May 2015 15:38:20 +0200 [thread overview]
Message-ID: <20150515133820.GA30744@1wt.eu> (raw)
In-Reply-To: <1431693140.6315.109.camel@decadent.org.uk>
Hi Ben,
On Fri, May 15, 2015 at 01:32:20PM +0100, Ben Hutchings wrote:
> On Fri, 2015-05-15 at 10:05 +0200, Willy Tarreau wrote:
> > 2.6.32-longterm review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Andy Lutomirski <luto@amacapital.net>
> >
> > commit f647d7c155f069c1a068030255c300663516420e upstream.
> >
> > Otherwise, if buggy user code points DS or ES into the TLS
> > array, they would be corrupted after a context switch.
> >
> > This also significantly improves the comments and documents some
> > gotchas in the code.
> >
> > Before this patch, the both tests below failed. With this
> > patch, the es test passes, although the gsbase test still fails.
> [...]
>
> This depends on the changes to FPU/MMX/SSE state management that you
> didn't apply to 2.6.32. Note this comment:
>
> /* Must be after DS reload */
> unlazy_fpu(prev_p);
Are you sure you're not confusing with another one ? When running
estest without this patch, I get "FAIL: ES corrupted 1000/1000 times"
while I get "OK: ES was preserved" once applied, so it does seem to
do what it's intended for.
Also I'm not seeing any reference to the comment above in the patch
nor around it, which leaves me confused :-/
Thanks,
Willy
next prev parent reply other threads:[~2015-05-15 13:38 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <9c2783dfae10ef2d1e9b08bcc1e562c5@local>
2015-05-15 8:05 ` [ 00/48] 2.6.32.66-longterm review Willy Tarreau
2015-05-15 8:05 ` [ 01/48] x86/asm/traps: Disable tracing and kprobes in fixup_bad_iret and sync_regs Willy Tarreau
2015-05-15 8:05 ` [ 02/48] x86/tls: Validate TLS entries to protect espfix Willy Tarreau
2015-05-15 8:05 ` [ 03/48] x86, tls, ldt: Stop checking lm in LDT_empty Willy Tarreau
2015-05-15 8:05 ` [ 04/48] x86, tls: Interpret an all-zero struct user_desc as "no segment" Willy Tarreau
2015-05-15 8:05 ` [ 05/48] x86_64, switch_to(): Load TLS descriptors before switching DS and ES Willy Tarreau
2015-05-15 12:32 ` Ben Hutchings
2015-05-15 13:38 ` Willy Tarreau [this message]
2015-05-15 14:25 ` Ben Hutchings
2015-05-15 14:31 ` Ben Hutchings
2015-05-15 14:37 ` Willy Tarreau
2015-05-15 15:53 ` Andi Kleen
2015-05-15 16:48 ` Willy Tarreau
2015-05-15 20:53 ` Ben Hutchings
2015-05-15 22:15 ` Andi Kleen
2015-05-15 8:05 ` [ 06/48] x86/tls: Disallow unusual TLS segments Willy Tarreau
2015-05-15 8:05 ` [ 07/48] x86/tls: Dont validate lm in set_thread_area() after all Willy Tarreau
2015-05-15 8:05 ` [ 08/48] x86, kvm: Clear paravirt_enabled on KVM guests for espfix32s benefit Willy Tarreau
2015-05-15 8:05 ` [ 09/48] x86_64, vdso: Fix the vdso address randomization algorithm Willy Tarreau
2015-05-15 21:02 ` Ben Hutchings
2015-05-15 8:05 ` [ 10/48] ASLR: fix stack randomization on 64-bit systems Willy Tarreau
2015-05-15 8:05 ` [ 11/48] x86, cpu, amd: Add workaround for family 16h, erratum 793 Willy Tarreau
2015-05-15 8:05 ` [ 12/48] x86/asm/entry/64: Remove a bogus ret_from_fork optimization Willy Tarreau
2015-05-15 8:05 ` [ 13/48] x86: Conditionally update time when ack-ing pending irqs Willy Tarreau
2015-05-15 8:05 ` [ 14/48] serial: samsung: wait for transfer completion before clock disable Willy Tarreau
2015-05-15 8:05 ` [ 15/48] splice: Apply generic position and size checks to each write Willy Tarreau
2015-05-15 8:05 ` [ 16/48] netfilter: conntrack: disable generic tracking for known protocols Willy Tarreau
2015-05-15 21:05 ` Ben Hutchings
2015-05-15 8:05 ` [ 17/48] isofs: Fix infinite looping over CE entries Willy Tarreau
2015-05-15 8:05 ` [ 18/48] isofs: Fix unchecked printing of ER records Willy Tarreau
2015-05-15 8:05 ` [ 19/48] net: sctp: fix memory leak in auth key management Willy Tarreau
2015-05-15 8:05 ` [ 20/48] net: sctp: fix slab corruption from use after free on INIT collisions Willy Tarreau
2015-05-15 8:05 ` [ 21/48] IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic Willy Tarreau
2015-05-15 8:05 ` [ 22/48] net: llc: use correct size for sysctl timeout entries Willy Tarreau
2015-05-15 8:05 ` [ 23/48] net: rds: use correct size for max unacked packets and bytes Willy Tarreau
2015-05-15 8:05 ` [ 24/48] ipv6: Dont reduce hop limit for an interface Willy Tarreau
2015-05-15 8:05 ` [ 25/48] fs: take i_mutex during prepare_binprm for set[ug]id executables Willy Tarreau
2015-05-15 8:05 ` [ 26/48] net:socket: set msg_namelen to 0 if msg_name is passed as NULL in msghdr struct from userland Willy Tarreau
2015-05-15 21:08 ` Ben Hutchings
2015-05-16 5:31 ` Willy Tarreau
2015-05-15 8:05 ` [ 27/48] ppp: deflate: never return len larger than output buffer Willy Tarreau
2015-05-15 8:05 ` [ 29/48] net: reject creation of netdev names with colons Willy Tarreau
2015-05-15 8:06 ` [ 30/48] ipv4: Dont use ufo handling on later transformed packets Willy Tarreau
2015-05-15 8:06 ` [ 31/48] udp: only allow UFO for packets from SOCK_DGRAM sockets Willy Tarreau
2015-05-15 8:06 ` [ 32/48] net: avoid to hang up on sending due to sysctl configuration overflow Willy Tarreau
2015-05-15 8:06 ` [ 33/48] net: sysctl_net_core: check SNDBUF and RCVBUF for min length Willy Tarreau
2015-05-15 8:06 ` [ 34/48] rds: avoid potential stack overflow Willy Tarreau
2015-05-15 8:06 ` [ 35/48] rxrpc: bogus MSG_PEEK test in rxrpc_recvmsg() Willy Tarreau
2015-05-15 8:06 ` [ 36/48] tcp: make connect() mem charging friendly Willy Tarreau
2015-05-15 8:06 ` [ 37/48] ip_forward: Drop frames with attached skb->sk Willy Tarreau
2015-05-15 8:06 ` [ 38/48] tcp: avoid looping in tcp_send_fin() Willy Tarreau
2015-05-15 8:06 ` [ 39/48] spi: spidev: fix possible arithmetic overflow for multi-transfer message Willy Tarreau
2015-05-15 8:06 ` [ 40/48] IB/core: Avoid leakage from kernel to user space Willy Tarreau
2015-05-15 8:06 ` [ 41/48] ipvs: uninitialized data with IP_VS_IPV6 Willy Tarreau
2015-05-15 8:06 ` [ 42/48] ipv4: fix nexthop attlen check in fib_nh_match Willy Tarreau
2015-05-15 8:06 ` [ 43/48] pagemap: do not leak physical addresses to non-privileged userspace Willy Tarreau
2015-05-15 8:06 ` [ 44/48] lockd: Try to reconnect if statd has moved Willy Tarreau
2015-05-15 8:06 ` [ 45/48] scsi: Fix error handling in SCSI_IOCTL_SEND_COMMAND Willy Tarreau
2015-05-15 8:06 ` [ 46/48] posix-timers: Fix stack info leak in timer_create() Willy Tarreau
2015-05-15 8:06 ` [ 47/48] hfsplus: fix B-tree corruption after insertion at position 0 Willy Tarreau
2015-05-15 8:06 ` [ 48/48] sound/oss: fix deadlock in sequencer_ioctl(SNDCTL_SEQ_OUTOFBAND) Willy Tarreau
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150515133820.GA30744@1wt.eu \
--to=w@1wt.eu \
--cc=andi@firstfloor.org \
--cc=ben@decadent.org.uk \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=mingo@kernel.org \
--cc=stable@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox