a207f59376
The probe function is supposed to return NULL on failure (as we can see in kobj_lookup: kobj = probe(dev, index, data); ... if (kobj) return kobj; However, in loop and brd, it returns negative error from ERR_PTR. This causes a crash if we simulate disk allocation failure and run less -f /dev/loop0 because the negative number is interpreted as a pointer: BUG: unable to handle kernel NULL pointer dereference at 00000000000002b4 IP: [<ffffffff8118b188>] __blkdev_get+0x28/0x450 PGD 23c677067 PUD 23d6d1067 PMD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: loop hpfs nvidia(PO) ip6table_filter ip6_tables uvesafb cfbcopyarea cfbimgblt cfbfillrect fbcon font bitblit fbcon_rotate fbcon_cw fbcon_ud fbcon_ccw softcursor fb fbdev msr ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 xt_state ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge stp llc tun ipv6 cpufreq_stats cpufreq_ondemand cpufreq_userspace cpufreq_powersave cpufreq_conservative hid_generic spadfs usbhid hid fuse raid0 snd_usb_audio snd_pcm_oss snd_mixer_oss md_mod snd_pcm snd_timer snd_page_alloc snd_hwdep snd_usbmidi_lib dmi_sysfs snd_rawmidi nf_nat_ftp nf_nat nf_conntrack_ftp nf_conntrack snd soundcore lm85 hwmon_vid ohci_hcd ehci_pci ehci_hcd serverworks sata_svw libata acpi_cpufreq freq_table mperf ide_core usbcore kvm_amd kvm tg3 i2c_piix4 libphy microcode e100 usb_common ptp skge i2c_core pcspkr k10temp evdev floppy hwmon pps_core mii rtc_cmos button processor unix [last unloaded: nvidia] CPU: 1 PID: 6831 Comm: less Tainted: P W O 3.10.15-devel #18 Hardware name: empty empty/S3992-E, BIOS 'V1.06 ' 06/09/2009 task: ffff880203cc6bc0 ti: ffff88023e47c000 task.ti: ffff88023e47c000 RIP: 0010:[<ffffffff8118b188>] [<ffffffff8118b188>] __blkdev_get+0x28/0x450 RSP: 0018:ffff88023e47dbd8 EFLAGS: 00010286 RAX: ffffffffffffff74 RBX: ffffffffffffff74 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff88023e47dc18 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88023f519658 R13: ffffffff8118c300 R14: 0000000000000000 R15: ffff88023f519640 FS: 00007f2070bf7700(0000) GS:ffff880247400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000002b4 CR3: 000000023da1d000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: 0000000000000002 0000001d00000000 000000003e47dc50 ffff88023f519640 ffff88043d5bb668 ffffffff8118c300 ffff88023d683550 ffff88023e47de60 ffff88023e47dc98 ffffffff8118c10d 0000001d81605698 0000000000000292 Call Trace: [<ffffffff8118c300>] ? blkdev_get_by_dev+0x60/0x60 [<ffffffff8118c10d>] blkdev_get+0x1dd/0x370 [<ffffffff8118c300>] ? blkdev_get_by_dev+0x60/0x60 [<ffffffff813cea6c>] ? _raw_spin_unlock+0x2c/0x50 [<ffffffff8118c300>] ? blkdev_get_by_dev+0x60/0x60 [<ffffffff8118c365>] blkdev_open+0x65/0x80 [<ffffffff8114d12e>] do_dentry_open.isra.18+0x23e/0x2f0 [<ffffffff8114d214>] finish_open+0x34/0x50 [<ffffffff8115e122>] do_last.isra.62+0x2d2/0xc50 [<ffffffff8115eb58>] path_openat.isra.63+0xb8/0x4d0 [<ffffffff81115a8e>] ? might_fault+0x4e/0xa0 [<ffffffff8115f4f0>] do_filp_open+0x40/0x90 [<ffffffff813cea6c>] ? _raw_spin_unlock+0x2c/0x50 [<ffffffff8116db85>] ? __alloc_fd+0xa5/0x1f0 [<ffffffff8114e45f>] do_sys_open+0xef/0x1d0 [<ffffffff8114e559>] SyS_open+0x19/0x20 [<ffffffff813cff16>] system_call_fastpath+0x1a/0x1f Code: 44 00 00 55 48 89 e5 41 57 49 89 ff 41 56 41 89 d6 41 55 41 54 4c 8d 67 18 53 48 83 ec 18 89 75 cc e9 f2 00 00 00 0f 1f 44 00 00 <48> 8b 80 40 03 00 00 48 89 df 4c 8b 68 58 e8 d5 a4 07 00 44 89 RIP [<ffffffff8118b188>] __blkdev_get+0x28/0x450 RSP <ffff88023e47dbd8> CR2: 00000000000002b4 ---[ end trace bb7f32dbf02398dc ]--- The brd change should be backported to stable kernels starting with 2.6.25. The loop change should be backported to stable kernels starting with 2.6.22. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: stable@kernel.org # 2.6.22+ Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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|---|---|---|
| .. | ||
| aoe | ||
| drbd | ||
| mtip32xx | ||
| paride | ||
| rsxx | ||
| xen-blkback | ||
| amiflop.c | ||
| ataflop.c | ||
| brd.c | ||
| cciss.c | ||
| cciss.h | ||
| cciss_cmd.h | ||
| cciss_scsi.c | ||
| cciss_scsi.h | ||
| cpqarray.c | ||
| cpqarray.h | ||
| cryptoloop.c | ||
| DAC960.c | ||
| DAC960.h | ||
| floppy.c | ||
| hd.c | ||
| ida_cmd.h | ||
| ida_ioctl.h | ||
| Kconfig | ||
| loop.c | ||
| loop.h | ||
| Makefile | ||
| mg_disk.c | ||
| nbd.c | ||
| nvme-core.c | ||
| nvme-scsi.c | ||
| osdblk.c | ||
| pktcdvd.c | ||
| ps3disk.c | ||
| ps3vram.c | ||
| rbd.c | ||
| rbd_types.h | ||
| smart1,2.h | ||
| sunvdc.c | ||
| swim.c | ||
| swim3.c | ||
| swim_asm.S | ||
| sx8.c | ||
| umem.c | ||
| umem.h | ||
| virtio_blk.c | ||
| xen-blkfront.c | ||
| xsysace.c | ||
| z2ram.c | ||