kernel/linux.git/block, branch v3.18.94

blk-mq: fix race between timeout and freeing request

2017-11-08T09:03:48+00:00

commit 0048b4837affd153897ed1222283492070027aa9 upstream. Inside timeout handler, blk_mq_tag_to_rq() is called to retrieve the request from one tag. This way is obviously wrong because the request can be freed any time and some fiedds of the request can't be trusted, then kernel oops might be triggered[1]. Currently wrt. blk_mq_tag_to_rq(), the only special case is that the flush request can share same tag with the request cloned from, and the two requests can't be active at the same time, so this patch fixes the above issue by updating tags->rqs[tag] with the active request(either flush rq or the request cloned from) of the tag. Also blk_mq_tag_to_rq() gets much simplified with this patch. Given blk_mq_tag_to_rq() is mainly for drivers and the caller must make sure the request can't be freed, so in bt_for_each() this helper is replaced with tags->rqs[tag]. [1] kernel oops log [ 439.696220] BUG: unable to handle kernel NULL pointer dereference at 0000000000000158^M [ 439.697162] IP: [] blk_mq_tag_to_rq+0x21/0x6e^M [ 439.700653] PGD 7ef765067 PUD 7ef764067 PMD 0 ^M [ 439.700653] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC ^M [ 439.700653] Dumping ftrace buffer:^M [ 439.700653] (ftrace buffer empty)^M [ 439.700653] Modules linked in: nbd ipv6 kvm_intel kvm serio_raw^M [ 439.700653] CPU: 6 PID: 2779 Comm: stress-ng-sigfd Not tainted 4.2.0-rc5-next-20150805+ #265^M [ 439.730500] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011^M [ 439.730500] task: ffff880605308000 ti: ffff88060530c000 task.ti: ffff88060530c000^M [ 439.730500] RIP: 0010:[] [] blk_mq_tag_to_rq+0x21/0x6e^M [ 439.730500] RSP: 0018:ffff880819203da0 EFLAGS: 00010283^M [ 439.730500] RAX: ffff880811b0e000 RBX: ffff8800bb465f00 RCX: 0000000000000002^M [ 439.730500] RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000^M [ 439.730500] RBP: ffff880819203db0 R08: 0000000000000002 R09: 0000000000000000^M [ 439.730500] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000202^M [ 439.730500] R13: ffff880814104800 R14: 0000000000000002 R15: ffff880811a2ea00^M [ 439.730500] FS: 00007f165b3f5740(0000) GS:ffff880819200000(0000) knlGS:0000000000000000^M [ 439.730500] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b^M [ 439.730500] CR2: 0000000000000158 CR3: 00000007ef766000 CR4: 00000000000006e0^M [ 439.730500] Stack:^M [ 439.730500] 0000000000000008 ffff8808114eed90 ffff880819203e00 ffffffff812dc104^M [ 439.755663] ffff880819203e40 ffffffff812d9f5e 0000020000000000 ffff8808114eed80^M [ 439.755663] Call Trace:^M [ 439.755663] ^M [ 439.755663] [] bt_for_each+0x6e/0xc8^M [ 439.755663] [] ? blk_mq_rq_timed_out+0x6a/0x6a^M [ 439.755663] [] ? blk_mq_rq_timed_out+0x6a/0x6a^M [ 439.755663] [] blk_mq_tag_busy_iter+0x55/0x5e^M [ 439.755663] [] ? blk_mq_bio_to_request+0x38/0x38^M [ 439.755663] [] blk_mq_rq_timer+0x5d/0xd4^M [ 439.755663] [] call_timer_fn+0xf7/0x284^M [ 439.755663] [] ? call_timer_fn+0x5/0x284^M [ 439.755663] [] ? blk_mq_bio_to_request+0x38/0x38^M [ 439.755663] [] run_timer_softirq+0x1ce/0x1f8^M [ 439.755663] [] __do_softirq+0x181/0x3a4^M [ 439.755663] [] irq_exit+0x40/0x94^M [ 439.755663] [] smp_apic_timer_interrupt+0x33/0x3e^M [ 439.755663] [] apic_timer_interrupt+0x84/0x90^M [ 439.755663] ^M [ 439.755663] [] ? _raw_spin_unlock_irq+0x32/0x4a^M [ 439.755663] [] finish_task_switch+0xe0/0x163^M [ 439.755663] [] ? finish_task_switch+0xa2/0x163^M [ 439.755663] [] __schedule+0x469/0x6cd^M [ 439.755663] [] schedule+0x82/0x9a^M [ 439.789267] [] signalfd_read+0x186/0x49a^M [ 439.790911] [] ? wake_up_q+0x47/0x47^M [ 439.790911] [] __vfs_read+0x28/0x9f^M [ 439.790911] [] ? __fget_light+0x4d/0x74^M [ 439.790911] [] vfs_read+0x7a/0xc6^M [ 439.790911] [] SyS_read+0x49/0x7f^M [ 439.790911] [] entry_SYSCALL_64_fastpath+0x12/0x6f^M [ 439.790911] Code: 48 89 e5 e8 a9 b8 e7 ff 5d c3 0f 1f 44 00 00 55 89 f2 48 89 e5 41 54 41 89 f4 53 48 8b 47 60 48 8b 1c d0 48 8b 7b 30 48 8b 53 38 <48> 8b 87 58 01 00 00 48 85 c0 75 09 48 8b 97 88 0c 00 00 eb 10 ^M [ 439.790911] RIP [] blk_mq_tag_to_rq+0x21/0x6e^M [ 439.790911] RSP ^M [ 439.790911] CR2: 0000000000000158^M [ 439.790911] ---[ end trace d40af58949325661 ]---^M Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Dmitry Shmidt Signed-off-by: Greg Kroah-Hartman

Revert "bsg-lib: don't free job in bsg_prepare_job"

2017-10-21T15:07:25+00:00

This reverts commit d9100405a20a71dd620843e0380e38fc50731108 which was commit f507b54dccfd8000c517d740bc45f20c74532d18 upstream. Ben reports: That function doesn't exist here (it was introduced in 4.13). Instead, this backport has modified bsg_create_job(), creating a leak. Please revert this on the 3.18, 4.4 and 4.9 stable branches. So I'm dropping it from here. Reported-by: Ben Hutchings Cc: Christoph Hellwig Cc: Ming Lei Cc: Jens Axboe Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

fix unbalanced page refcounting in bio_map_user_iov

2017-10-18T07:15:16+00:00

commit 95d78c28b5a85bacbc29b8dba7c04babb9b0d467 upstream. bio_map_user_iov and bio_unmap_user do unbalanced pages refcounting if IO vector has small consecutive buffers belonging to the same page. bio_add_pc_page merges them into one, but the page reference is never dropped. Signed-off-by: Vitaly Mayatskikh Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

partitions/efi: Fix integer overflow in GPT size calculation

2017-10-08T08:11:20+00:00

[ Upstream commit c5082b70adfe8e1ea1cf4a8eff92c9f260e364d2 ] If a GUID Partition Table claims to have more than 2**25 entries, the calculation of the partition table size in alloc_read_gpt_entries() will overflow a 32-bit integer and not enough space will be allocated for the table. Nothing seems to get written out of bounds, but later efi_partition() will read up to 32768 bytes from a 128 byte buffer, possibly OOPSing or exposing information to /proc/partitions and uevents. The problem exists on both 64-bit and 32-bit platforms. Fix the overflow and also print a meaningful debug message if the table size is too large. Signed-off-by: Alden Tondettar Acked-by: Ard Biesheuvel Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bsg-lib: don't free job in bsg_prepare_job

2017-10-05T07:35:52+00:00

commit f507b54dccfd8000c517d740bc45f20c74532d18 upstream. The job structure is allocated as part of the request, so we should not free it in the error path of bsg_prepare_job. Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: Relax a check in blk_start_queue()

2017-09-27T08:57:19+00:00

commit 4ddd56b003f251091a67c15ae3fe4a5c5c5e390a upstream. Calling blk_start_queue() from interrupt context with the queue lock held and without disabling IRQs, as the skd driver does, is safe. This patch avoids that loading the skd driver triggers the following warning: WARNING: CPU: 11 PID: 1348 at block/blk-core.c:283 blk_start_queue+0x84/0xa0 RIP: 0010:blk_start_queue+0x84/0xa0 Call Trace: skd_unquiesce_dev+0x12a/0x1d0 [skd] skd_complete_internal+0x1e7/0x5a0 [skd] skd_complete_other+0xc2/0xd0 [skd] skd_isr_completion_posted.isra.30+0x2a5/0x470 [skd] skd_isr+0x14f/0x180 [skd] irq_forced_thread_fn+0x2a/0x70 irq_thread+0x144/0x1a0 kthread+0x125/0x140 ret_from_fork+0x2a/0x40 Fixes: commit a038e2536472 ("[PATCH] blk_start_queue() must be called with irq disabled - add warning") Signed-off-by: Bart Van Assche Cc: Paolo 'Blaisorblade' Giarrusso Cc: Andrew Morton Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Johannes Thumshirn Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

partitions/msdos: FreeBSD UFS2 file systems are not recognized

2017-06-26T05:10:48+00:00

commit 223220356d5ebc05ead9a8d697abb0c0a906fc81 upstream. The code in block/partitions/msdos.c recognizes FreeBSD, OpenBSD and NetBSD partitions and does a reasonable job picking out OpenBSD and NetBSD UFS subpartitions. But for FreeBSD the subpartitions are always "bad". Kernel: Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: allow WRITE_SAME commands with the SG_IO ioctl

2017-04-22T05:15:06+00:00

commit 25cdb64510644f3e854d502d69c73f21c6df88a9 upstream. The WRITE_SAME commands are not present in the blk_default_cmd_filter write_ok list, and thus are failed with -EPERM when the SG_IO ioctl() is executed without CAP_SYS_RAWIO capability (e.g., unprivileged users). [ sg_io() -> blk_fill_sghdr_rq() > blk_verify_command() -> -EPERM ] The problem can be reproduced with the sg_write_same command # sg_write_same --num 1 --xferlen 512 /dev/sda # # capsh --drop=cap_sys_rawio -- -c \ 'sg_write_same --num 1 --xferlen 512 /dev/sda' Write same: pass through os error: Operation not permitted # For comparison, the WRITE_VERIFY command does not observe this problem, since it is in that list: # capsh --drop=cap_sys_rawio -- -c \ 'sg_write_verify --num 1 --ilen 512 --lba 0 /dev/sda' # So, this patch adds the WRITE_SAME commands to the list, in order for the SG_IO ioctl to finish successfully: # capsh --drop=cap_sys_rawio -- -c \ 'sg_write_same --num 1 --xferlen 512 /dev/sda' # That case happens to be exercised by QEMU KVM guests with 'scsi-block' devices (qemu "-device scsi-block" [1], libvirt "" [2]), which employs the SG_IO ioctl() and runs as an unprivileged user (libvirt-qemu). In that scenario, when a filesystem (e.g., ext4) performs its zero-out calls, which are translated to write-same calls in the guest kernel, and then into SG_IO ioctls to the host kernel, SCSI I/O errors may be observed in the guest: [...] sd 0:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [...] sd 0:0:0:0: [sda] tag#0 Sense Key : Aborted Command [current] [...] sd 0:0:0:0: [sda] tag#0 Add. Sense: I/O process terminated [...] sd 0:0:0:0: [sda] tag#0 CDB: Write Same(10) 41 00 01 04 e0 78 00 00 08 00 [...] blk_update_request: I/O error, dev sda, sector 17096824 Links: [1] http://git.qemu.org/?p=qemu.git;a=commit;h=336a6915bc7089fb20fea4ba99972ad9a97c5f52 [2] https://libvirt.org/formatdomain.html#elementsDisks (see 'disk' -> 'device') Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Brahadambal Srinivasan Reported-by: Manjunatha H R Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

sg_write()/bsg_write() is not fit to be called under KERNEL_DS

2017-01-15T14:49:53+00:00

[ Upstream commit 128394eff343fc6d2f32172f03e24829539c5835 ] Both damn things interpret userland pointers embedded into the payload; worse, they are actually traversing those. Leaving aside the bad API design, this is very much _not_ safe to call with KERNEL_DS. Bail out early if that happens. Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Sasha Levin

block: Do a full clone when splitting discard bios

2016-10-07T14:37:27+00:00

This fixes a data corruption bug when using discard on top of MD linear, raid0 and raid10 personalities. Commit 20d0189b1012 "block: Introduce new bio_split()" permits sharing the bio_vec between the two resulting bios. That is fine for read/write requests where the bio_vec is immutable. For discards, however, we need to be able to attach a payload and update the bio_vec so the page can get mapped to a scatterlist entry. Therefore the bio_vec can not be shared when splitting discards and we must do a full clone. Signed-off-by: Martin K. Petersen Reported-by: Seunguk Shin Tested-by: Seunguk Shin Cc: Seunguk Shin Cc: Jens Axboe Cc: Kent Overstreet Cc: # v3.14+ Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe