From: Arnd Bergmann <arnd@arndb.de> To: Andrew Hendry <andrew.hendry@gmail.com> Cc: linux-kernel@vger.kernel.org, linux-x25@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 12/20] x25: remove the BKL Date: Thu, 27 Jan 2011 13:17:01 +0100 [thread overview] Message-ID: <201101271317.01502.arnd@arndb.de> (raw) In-Reply-To: <AANLkTim=d4Tok-ri1BozZUfBFS=rofaodN8ZBA5AjKKd@mail.gmail.com> On Thursday 27 January 2011, Andrew Hendry wrote: > Left it running and put about 3.0G through x.25, it was running fine > until after about 20 hours. > I was stopping the test programs and hit this. > > Jan 27 20:18:34 jaunty kernel: [80403.945790] PGD 1d8b00067 PUD 1ddec3067 PMD 0 Is there no long above this about what problem was hit? There is normally one saying things like "Bug: unable to handle ..." Well, nevermind. It seems I could figure it out anyway: > Jan 27 20:18:34 jaunty kernel: [80403.946083] RAX: 0000000000000080 RBX: ffff880228dbfd70 RCX: ffff880228dbfce4 > Jan 27 20:18:34 jaunty kernel: [80403.946096] RDX: 00000000fffffe00 RSI: 0000000000000000 RDI: ffff8801ba89f050 > Jan 27 20:18:34 jaunty kernel: [80403.946109] RBP: ffff880228dbfd18 R08: ffff88022aa91000 R09: 0000000000000000 > Jan 27 20:18:34 jaunty kernel: [80403.946482] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801ba89f000 > Jan 27 20:18:34 jaunty kernel: [80403.946495] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > ... > > If i have done it right, x25_sendmsg+0x1a7/0x530 is the skb_reserve > which gets inlined here. > (af_x25.c) > /* Build a packet */ > SOCK_DEBUG(sk, "x25_sendmsg: sendto: building packet.\n"); > > if ((msg->msg_flags & MSG_OOB) && len > 32) > len = 32; > > size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN; > > release_sock(sk); > skb = sock_alloc_send_skb(sk, size, noblock, &rc); > lock_sock(sk); > > X25_SKB_CB(skb)->flags = msg->msg_flags; ok. > objdump -dS show it at 2197 here. > > static inline void skb_reserve(struct sk_buff *skb, int len) > { > skb->data += len; > skb->tail += len; > 2197: 41 83 87 b4 00 00 00 addl $0x16,0xb4(%r15) <--- > 219e: 16 > 219f: 41 89 47 28 mov %eax,0x28(%r15) > 21a3: 49 8b 87 c8 00 00 00 mov 0xc8(%r15),%rax > 21aa: 48 83 c0 16 add $0x16,%rax > skb_reserve(skb, X25_MAX_L2_LEN + X25_EXT_MIN_LEN); > > But im not sure where to go from there... It's pretty clear that %r15 is the skb in this, and from the registers in the dump, you can see that it's NULL. skb has just been returned from sock_alloc_send_skb, which means that this function failed. And indeed: > > @@ -1148,9 +1140,10 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock, > > > > size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN; > > > > + release_sock(sk); > > skb = sock_alloc_send_skb(sk, size, noblock, &rc); > > - if (!skb) > > - goto out; > > + lock_sock(sk); > > + > > X25_SKB_CB(skb)->flags = msg->msg_flags; I accidentally removed the error handling in my patch. No idea how that happened, it certainly wasn't intentional. Thanks a lot for the thorough testing and the detailed bug report! I'll follow up with a fixed patch that puts the error path back in. Arnd
next prev parent reply other threads:[~2011-01-27 12:17 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-01-25 22:17 [RFC 00/20] Proposal for remaining BKL users Arnd Bergmann 2011-01-25 22:17 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 01/20] drm/i810: remove the BKL Arnd Bergmann 2011-01-25 22:17 ` [PATCH 02/20] drm: remove i830 driver Arnd Bergmann 2011-01-25 22:17 ` [PATCH 03/20] staging/usbip: convert to kthread Arnd Bergmann 2011-01-28 17:53 ` Max Vozeler 2011-01-28 18:48 ` Arnd Bergmann 2011-03-01 22:15 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 04/20] staging/cx25721: serialize access to devlist Arnd Bergmann 2011-01-26 16:23 ` Palash Bandyopadhyay 2011-01-31 21:37 ` Greg KH 2011-01-25 22:17 ` [PATCH 05/20] staging/go7007: remove the BKL Arnd Bergmann 2011-01-25 22:17 ` [PATCH 06/20] staging: Remove autofs3 Arnd Bergmann 2011-01-26 7:41 ` H. Peter Anvin 2011-01-25 22:17 ` [PATCH 07/20] staging: remove smbfs Arnd Bergmann 2011-01-25 22:17 ` [PATCH 08/20] adfs: remove the big kernel lock Arnd Bergmann 2011-01-25 22:20 ` Russell King 2011-01-25 22:17 ` [PATCH 09/20] hpfs: rename big kernel lock to hpfs_lock Arnd Bergmann 2011-01-25 22:17 ` [PATCH 10/20] hpfs: replace BKL with a global mutex Arnd Bergmann 2011-01-26 0:15 ` Andi Kleen 2011-01-26 0:19 ` Andi Kleen 2011-01-26 12:48 ` [PATCH v2] hpfs: remove the BKL Arnd Bergmann 2011-01-26 12:50 ` [PATCH 10/20] hpfs: replace BKL with a global mutex Arnd Bergmann 2011-01-26 16:52 ` Andi Kleen 2011-01-27 5:01 ` Nick Piggin 2011-01-27 10:57 ` Miklos Szeredi 2011-01-25 22:17 ` [PATCH 11/20] hpfs: move to drivers/staging Arnd Bergmann 2011-02-07 16:17 ` Mikulas Patocka 2011-02-07 19:31 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 12/20] x25: remove the BKL Arnd Bergmann 2011-01-27 10:07 ` Andrew Hendry 2011-01-27 12:17 ` Arnd Bergmann [this message] 2011-01-27 12:38 ` [PATCH v2] " Arnd Bergmann 2011-01-27 13:20 ` Eric Dumazet 2011-01-27 13:43 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 13/20] appletalk: move to staging Arnd Bergmann 2011-01-25 22:17 ` [PATCH 14/20] staging/appletalk: remove the BKL Arnd Bergmann 2011-01-25 22:29 ` David Miller 2011-01-26 12:57 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 15/20] ufs: " Arnd Bergmann 2011-01-26 2:30 ` Nick Bowler 2011-01-26 12:53 ` Arnd Bergmann 2011-01-27 5:47 ` Nick Piggin 2011-01-27 13:13 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 16/20] ipx: " Arnd Bergmann 2011-01-25 22:17 ` [PATCH 17/20] tracing: don't trace " Arnd Bergmann 2011-01-25 22:28 ` Frederic Weisbecker 2011-01-25 22:17 ` [PATCH 18/20] rtmutex-tester: remove BKL tests Arnd Bergmann 2011-01-26 15:00 ` [tip:core/locking] rtmutex-tester: Remove " tip-bot for Arnd Bergmann 2011-02-22 20:57 ` [tip:irq/core] rtmutex: tester: " tip-bot for Arnd Bergmann 2011-01-25 22:17 ` [PATCH 19/20] drivers: remove extraneous includes of smp_lock.h Arnd Bergmann 2011-01-25 22:17 ` [PATCH 20/20] BKL: That's all, folks Arnd Bergmann 2011-01-26 6:19 ` Ingo Molnar 2011-01-26 8:47 ` Alan Cox 2011-01-26 11:01 ` Ingo Molnar 2011-01-26 11:22 ` Thomas Gleixner 2011-01-26 2:22 ` [RFC 00/20] Proposal for remaining BKL users Greg KH 2011-01-26 2:22 ` Greg KH 2011-01-26 11:31 ` Arnd Bergmann 2011-01-26 11:31 ` Arnd Bergmann 2011-01-26 11:58 ` Mauro Carvalho Chehab 2011-01-26 13:45 ` Arnd Bergmann 2011-01-26 13:45 ` Arnd Bergmann 2011-01-26 16:24 ` Palash Bandyopadhyay
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