| Message ID | s5hioirqh6m.wl-tiwai@suse.de |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
Hi Takashi, yes, this no longer crashes. No real-world test yet, but the obvious crash is gone. Thanks! Am 07.11.2014 um 14:22 schrieb Takashi Iwai: > At Fri, 07 Nov 2014 12:10:46 +0100, > Stefan Seyfried wrote: >> >> Hi all, >> >> since 3.18-rc1, setting up a PPP interface kills my kernel with >> >> [ 163.433251] PPP generic driver version 2.4.2 >> [ 164.452474] ------------[ cut here ]------------ >> [ 164.453327] kernel BUG at ../mm/vmalloc.c:1316! >> [ 164.453327] invalid opcode: 0000 [#1] PREEMPT SMP >> [ 164.453327] Modules linked in: ppp_async crc_ccitt ppp_generic slhc af_packet xfs libcrc32c coretemp kvm_intel >> snd_hda_codec_conexant iTCO_wdt snd_hda_codec_generic iTCO_vendor_support uvcvideo snd_hda_intel snd_hda_controller mac80211 videobuf2_vmalloc snd_hda_codec kvm e1000e videobuf2_memops cfg80211 videobuf2_core v4l2_common snd_hwdep i2c_i801 videodev snd_pcm pcspkr thinkpad_acpi serio_raw wmi lpc_ich snd_timer thermal snd rfkill mfd_core tpm_tis shpchp mei_me soundcore ptp mei pps_core acpi_cpufreq tpm battery processor ac dm_mod btrfs xor raid6_pq i915 i2c_algo_bit drm_kms_helper drm video button sg >> [ 164.453327] CPU: 0 PID: 6927 Comm: pppd Not tainted 3.18.0-rc3-3.ge706e91-desktop #1 >> [ 164.453327] Hardware name: LENOVO 7470E36/7470E36, BIOS 6DET61WW (3.11 ) 11/10/2009 >> >> This is easy to reproduce with: >> >> linux:~ # cat bin/crashme.sh >> ---- >> #!/bin/bash -x >> pppd local pty "netcat -l 1234" & >> sleep 1 >> pppd local pty "netcat localhost 1234" & >> sleep 1 >> ---- >> >> 3.17 works fine. >> I bisected the issue multiple times and always arrived at >> >> # first bad commit: [d6dd50e07c5bec00db2005969b1a01f8ca3d25ef] Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip >> >> which is a merge commit unfortunately. >> >> The BUG encountered above is in: >> >> 1309 static struct vm_struct *__get_vm_area_node(unsigned long size, >> 1310 unsigned long align, unsigned long flags, unsigned long start, >> 1311 unsigned long end, int node, gfp_t gfp_mask, const void *caller) >> 1312 { >> 1313 struct vmap_area *va; >> 1314 struct vm_struct *area; >> 1315 >> 1316 BUG_ON(in_interrupt()); >> 1317 if (flags & VM_IOREMAP) >> 1318 align = 1ul << clamp(fls(size), PAGE_SHIFT, IOREMAP_MAX_ORDER); >> 1319 >> >> the call trace is: >> [ 164.453327] Call Trace: >> [ 164.453327] [<ffffffff811974bd>] __vmalloc_node_range+0x6d/0x290 >> [ 164.453327] [<ffffffff8119771e>] __vmalloc+0x3e/0x50 >> [ 164.453327] [<ffffffff81146950>] bpf_prog_alloc+0x30/0xa0 >> [ 164.453327] [<ffffffff8157b716>] bpf_prog_create+0x46/0xb0 >> [ 164.453327] [<ffffffffa07ecb90>] ppp_ioctl+0x420/0xe9a [ppp_generic] >> [ 164.453327] [<ffffffff811df1c7>] do_vfs_ioctl+0x2e7/0x4c0 >> [ 164.453327] [<ffffffff811df421>] SyS_ioctl+0x81/0xa0 >> [ 164.453327] [<ffffffff8165ee2d>] system_call_fastpath+0x16/0x1b >> [ 164.453327] [<00007f4502d87397>] 0x7f4502d87397 > > bpf_prog_create() is called inside spin_lock_bh(), and the BUG_ON() > hits. Below is a quick fix. > > > Takashi > > -- 8< -- > From: Takashi Iwai <tiwai@suse.de> > Subject: [PATCH] net: ppp: Don't call bpf_prog_create() in ppp_lock > > In ppp_ioctl(), bpf_prog_create() is called inside ppp_lock, which > eventually calls vmalloc() and hits BUG_ON() in vmalloc.c. This patch > works around the problem by moving the allocation outside the lock. > > Reported-by: Stefan Seyfried <stefan.seyfried@googlemail.com> > Signed-off-by: Takashi Iwai <tiwai@suse.de> FWIW :-) Tested-by: Stefan Seyfried <stefan.seyfried@googlemail.com> > --- > drivers/net/ppp/ppp_generic.c | 40 ++++++++++++++++++++-------------------- > 1 file changed, 20 insertions(+), 20 deletions(-) > > diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c > index 68c3a3f4e0ab..794a47329368 100644 > --- a/drivers/net/ppp/ppp_generic.c > +++ b/drivers/net/ppp/ppp_generic.c > @@ -755,23 +755,23 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > > err = get_filter(argp, &code); > if (err >= 0) { > + struct bpf_prog *pass_filter = NULL; > struct sock_fprog_kern fprog = { > .len = err, > .filter = code, > }; > > - ppp_lock(ppp); > - if (ppp->pass_filter) { > - bpf_prog_destroy(ppp->pass_filter); > - ppp->pass_filter = NULL; > + err = 0; > + if (fprog.filter) > + err = bpf_prog_create(&pass_filter, &fprog); > + if (!err) { > + ppp_lock(ppp); > + if (ppp->pass_filter) > + bpf_prog_destroy(ppp->pass_filter); > + ppp->pass_filter = pass_filter; > + ppp_unlock(ppp); > } > - if (fprog.filter != NULL) > - err = bpf_prog_create(&ppp->pass_filter, > - &fprog); > - else > - err = 0; > kfree(code); > - ppp_unlock(ppp); > } > break; > } > @@ -781,23 +781,23 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > > err = get_filter(argp, &code); > if (err >= 0) { > + struct bpf_prog *active_filter = NULL; > struct sock_fprog_kern fprog = { > .len = err, > .filter = code, > }; > > - ppp_lock(ppp); > - if (ppp->active_filter) { > - bpf_prog_destroy(ppp->active_filter); > - ppp->active_filter = NULL; > + err = 0; > + if (fprog.filter) > + err = bpf_prog_create(&active_filter, &fprog); > + if (!err) { > + ppp_lock(ppp); > + if (ppp->active_filter) > + bpf_prog_destroy(ppp->active_filter); > + ppp->active_filter = active_filter; > + ppp_unlock(ppp); > } > - if (fprog.filter != NULL) > - err = bpf_prog_create(&ppp->active_filter, > - &fprog); > - else > - err = 0; > kfree(code); > - ppp_unlock(ppp); > } > break; > } >
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index 68c3a3f4e0ab..794a47329368 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -755,23 +755,23 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) err = get_filter(argp, &code); if (err >= 0) { + struct bpf_prog *pass_filter = NULL; struct sock_fprog_kern fprog = { .len = err, .filter = code, }; - ppp_lock(ppp); - if (ppp->pass_filter) { - bpf_prog_destroy(ppp->pass_filter); - ppp->pass_filter = NULL; + err = 0; + if (fprog.filter) + err = bpf_prog_create(&pass_filter, &fprog); + if (!err) { + ppp_lock(ppp); + if (ppp->pass_filter) + bpf_prog_destroy(ppp->pass_filter); + ppp->pass_filter = pass_filter; + ppp_unlock(ppp); } - if (fprog.filter != NULL) - err = bpf_prog_create(&ppp->pass_filter, - &fprog); - else - err = 0; kfree(code); - ppp_unlock(ppp); } break; } @@ -781,23 +781,23 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) err = get_filter(argp, &code); if (err >= 0) { + struct bpf_prog *active_filter = NULL; struct sock_fprog_kern fprog = { .len = err, .filter = code, }; - ppp_lock(ppp); - if (ppp->active_filter) { - bpf_prog_destroy(ppp->active_filter); - ppp->active_filter = NULL; + err = 0; + if (fprog.filter) + err = bpf_prog_create(&active_filter, &fprog); + if (!err) { + ppp_lock(ppp); + if (ppp->active_filter) + bpf_prog_destroy(ppp->active_filter); + ppp->active_filter = active_filter; + ppp_unlock(ppp); } - if (fprog.filter != NULL) - err = bpf_prog_create(&ppp->active_filter, - &fprog); - else - err = 0; kfree(code); - ppp_unlock(ppp); } break; }