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* KASAN: use-after-free Read in iov_iter_alignment
@ 2019-12-02 17:15 syzbot
  2019-12-02 21:10 ` Dave Chinner
  0 siblings, 1 reply; 3+ messages in thread
From: syzbot @ 2019-12-02 17:15 UTC (permalink / raw)
  To: darrick.wong, hch, linux-fsdevel, linux-kernel, linux-xfs,
	syzkaller-bugs

Hello,

syzbot found the following crash on:

HEAD commit:    b94ae8ad Merge tag 'seccomp-v5.5-rc1' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=135a8d7ae00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c2e464ae414aee8c
dashboard link: https://syzkaller.appspot.com/bug?extid=bea68382bae9490e7dd6
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1135cb36e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14e90abce00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+bea68382bae9490e7dd6@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in iov_iter_alignment+0x6a1/0x7b0  
lib/iov_iter.c:1225
Read of size 4 at addr ffff888098d40f54 by task loop0/8203

CPU: 0 PID: 8203 Comm: loop0 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1fb/0x318 lib/dump_stack.c:118
  print_address_description+0x75/0x5c0 mm/kasan/report.c:374
  __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
  kasan_report+0x26/0x50 mm/kasan/common.c:634
  __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
  iov_iter_alignment+0x6a1/0x7b0 lib/iov_iter.c:1225
  iomap_dio_bio_actor+0x1a7/0x11e0 fs/iomap/direct-io.c:203
  iomap_dio_actor+0x2b4/0x4a0 fs/iomap/direct-io.c:375
  iomap_apply+0x370/0x490 fs/iomap/apply.c:80
  iomap_dio_rw+0x8ad/0x1010 fs/iomap/direct-io.c:493
  ext4_dio_read_iter fs/ext4/file.c:77 [inline]
  ext4_file_read_iter+0x834/0xc20 fs/ext4/file.c:128
  lo_rw_aio+0xcbb/0xea0 include/linux/fs.h:1889
  do_req_filebacked drivers/block/loop.c:616 [inline]
  loop_handle_cmd drivers/block/loop.c:1952 [inline]
  loop_queue_work+0x13ab/0x2590 drivers/block/loop.c:1966
  kthread_worker_fn+0x449/0x700 kernel/kthread.c:671
  loop_kthread_worker_fn+0x40/0x60 drivers/block/loop.c:901
  kthread+0x332/0x350 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 4198:
  save_stack mm/kasan/common.c:69 [inline]
  set_track mm/kasan/common.c:77 [inline]
  __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:510
  kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:518
  slab_post_alloc_hook mm/slab.h:584 [inline]
  slab_alloc mm/slab.c:3319 [inline]
  kmem_cache_alloc+0x1f5/0x2e0 mm/slab.c:3483
  mempool_alloc_slab+0x4d/0x70 mm/mempool.c:513
  mempool_alloc+0x104/0x5e0 mm/mempool.c:393
  bio_alloc_bioset+0x1b0/0x5f0 block/bio.c:477
  bio_alloc include/linux/bio.h:400 [inline]
  mpage_alloc fs/mpage.c:79 [inline]
  do_mpage_readpage+0x1685/0x1d10 fs/mpage.c:306
  mpage_readpages+0x2a9/0x440 fs/mpage.c:404
  blkdev_readpages+0x2c/0x40 fs/block_dev.c:620
  read_pages+0xad/0x4d0 mm/readahead.c:126
  __do_page_cache_readahead+0x480/0x530 mm/readahead.c:212
  force_page_cache_readahead mm/readahead.c:243 [inline]
  page_cache_sync_readahead+0x329/0x3b0 mm/readahead.c:522
  generic_file_buffered_read+0x41d/0x2570 mm/filemap.c:2051
  generic_file_read_iter+0xa9/0x450 mm/filemap.c:2324
  blkdev_read_iter+0x12e/0x140 fs/block_dev.c:2039
  call_read_iter include/linux/fs.h:1889 [inline]
  new_sync_read fs/read_write.c:414 [inline]
  __vfs_read+0x59e/0x730 fs/read_write.c:427
  vfs_read+0x1dd/0x420 fs/read_write.c:461
  ksys_read+0x117/0x220 fs/read_write.c:587
  __do_sys_read fs/read_write.c:597 [inline]
  __se_sys_read fs/read_write.c:595 [inline]
  __x64_sys_read+0x7b/0x90 fs/read_write.c:595
  do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4205:
  save_stack mm/kasan/common.c:69 [inline]
  set_track mm/kasan/common.c:77 [inline]
  kasan_set_free_info mm/kasan/common.c:332 [inline]
  __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:471
  kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
  __cache_free mm/slab.c:3425 [inline]
  kmem_cache_free+0x81/0xf0 mm/slab.c:3693
  mempool_free_slab+0x1d/0x30 mm/mempool.c:520
  mempool_free+0xd5/0x350 mm/mempool.c:502
  bio_put+0x38b/0x460 block/bio.c:255
  mpage_end_io+0x2f5/0x330 fs/mpage.c:58
  bio_endio+0x4ff/0x570 block/bio.c:1818
  req_bio_endio block/blk-core.c:245 [inline]
  blk_update_request+0x438/0x10d0 block/blk-core.c:1464
  scsi_end_request+0x8c/0xa20 drivers/scsi/scsi_lib.c:579
  scsi_io_completion+0x17c/0x1b80 drivers/scsi/scsi_lib.c:963
  scsi_finish_command+0x3b3/0x560 drivers/scsi/scsi.c:228
  scsi_softirq_done+0x289/0x310 drivers/scsi/scsi_lib.c:1477
  blk_done_softirq+0x312/0x370 block/blk-softirq.c:37
  __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:762

The buggy address belongs to the object at ffff888098d40f00
  which belongs to the cache bio-0 of size 192
The buggy address is located 84 bytes inside of
  192-byte region [ffff888098d40f00, ffff888098d40fc0)
The buggy address belongs to the page:
page:ffffea0002635000 refcount:1 mapcount:0 mapping:ffff88821acf5700  
index:0xffff888098d40c00
raw: 00fffe0000000200 ffffea0002805188 ffff8880a7b42738 ffff88821acf5700
raw: ffff888098d40c00 ffff888098d40000 000000010000000e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff888098d40e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff888098d40e80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
> ffff888098d40f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                  ^
  ffff888098d40f80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
  ffff888098d41000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: KASAN: use-after-free Read in iov_iter_alignment
  2019-12-02 17:15 KASAN: use-after-free Read in iov_iter_alignment syzbot
@ 2019-12-02 21:10 ` Dave Chinner
  2019-12-02 23:11   ` Matthew Bobrowski
  0 siblings, 1 reply; 3+ messages in thread
From: Dave Chinner @ 2019-12-02 21:10 UTC (permalink / raw)
  To: syzbot
  Cc: darrick.wong, hch, linux-fsdevel, linux-kernel, linux-xfs,
	syzkaller-bugs, linux-ext4

[cc linux-ext4@vger.kernel.org - this is reported from the new ext4
dio->iomap code]

On Mon, Dec 02, 2019 at 09:15:08AM -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    b94ae8ad Merge tag 'seccomp-v5.5-rc1' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=135a8d7ae00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c2e464ae414aee8c
> dashboard link: https://syzkaller.appspot.com/bug?extid=bea68382bae9490e7dd6
> compiler:       clang version 9.0.0 (/home/glider/llvm/clang
> 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1135cb36e00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14e90abce00000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+bea68382bae9490e7dd6@syzkaller.appspotmail.com
> 
> ==================================================================
> BUG: KASAN: use-after-free in iov_iter_alignment+0x6a1/0x7b0
> lib/iov_iter.c:1225
> Read of size 4 at addr ffff888098d40f54 by task loop0/8203
> 
> CPU: 0 PID: 8203 Comm: loop0 Not tainted 5.4.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x1fb/0x318 lib/dump_stack.c:118
>  print_address_description+0x75/0x5c0 mm/kasan/report.c:374
>  __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
>  kasan_report+0x26/0x50 mm/kasan/common.c:634
>  __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
>  iov_iter_alignment+0x6a1/0x7b0 lib/iov_iter.c:1225
>  iomap_dio_bio_actor+0x1a7/0x11e0 fs/iomap/direct-io.c:203
>  iomap_dio_actor+0x2b4/0x4a0 fs/iomap/direct-io.c:375
>  iomap_apply+0x370/0x490 fs/iomap/apply.c:80
>  iomap_dio_rw+0x8ad/0x1010 fs/iomap/direct-io.c:493
>  ext4_dio_read_iter fs/ext4/file.c:77 [inline]
>  ext4_file_read_iter+0x834/0xc20 fs/ext4/file.c:128
>  lo_rw_aio+0xcbb/0xea0 include/linux/fs.h:1889

loopback -> ext4 direct IO, bad access on iov passed to iomap DIO
code.

>  do_req_filebacked drivers/block/loop.c:616 [inline]
>  loop_handle_cmd drivers/block/loop.c:1952 [inline]
>  loop_queue_work+0x13ab/0x2590 drivers/block/loop.c:1966
>  kthread_worker_fn+0x449/0x700 kernel/kthread.c:671
>  loop_kthread_worker_fn+0x40/0x60 drivers/block/loop.c:901
>  kthread+0x332/0x350 kernel/kthread.c:255
>  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> 
> Allocated by task 4198:
>  save_stack mm/kasan/common.c:69 [inline]
>  set_track mm/kasan/common.c:77 [inline]
>  __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:510
>  kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:518
>  slab_post_alloc_hook mm/slab.h:584 [inline]
>  slab_alloc mm/slab.c:3319 [inline]
>  kmem_cache_alloc+0x1f5/0x2e0 mm/slab.c:3483
>  mempool_alloc_slab+0x4d/0x70 mm/mempool.c:513
>  mempool_alloc+0x104/0x5e0 mm/mempool.c:393
>  bio_alloc_bioset+0x1b0/0x5f0 block/bio.c:477
>  bio_alloc include/linux/bio.h:400 [inline]
>  mpage_alloc fs/mpage.c:79 [inline]
>  do_mpage_readpage+0x1685/0x1d10 fs/mpage.c:306
>  mpage_readpages+0x2a9/0x440 fs/mpage.c:404
>  blkdev_readpages+0x2c/0x40 fs/block_dev.c:620
>  read_pages+0xad/0x4d0 mm/readahead.c:126
>  __do_page_cache_readahead+0x480/0x530 mm/readahead.c:212
>  force_page_cache_readahead mm/readahead.c:243 [inline]
>  page_cache_sync_readahead+0x329/0x3b0 mm/readahead.c:522
>  generic_file_buffered_read+0x41d/0x2570 mm/filemap.c:2051
>  generic_file_read_iter+0xa9/0x450 mm/filemap.c:2324
>  blkdev_read_iter+0x12e/0x140 fs/block_dev.c:2039
>  call_read_iter include/linux/fs.h:1889 [inline]
>  new_sync_read fs/read_write.c:414 [inline]
>  __vfs_read+0x59e/0x730 fs/read_write.c:427
>  vfs_read+0x1dd/0x420 fs/read_write.c:461
>  ksys_read+0x117/0x220 fs/read_write.c:587
>  __do_sys_read fs/read_write.c:597 [inline]
>  __se_sys_read fs/read_write.c:595 [inline]
>  __x64_sys_read+0x7b/0x90 fs/read_write.c:595
>  do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> Freed by task 4205:
>  save_stack mm/kasan/common.c:69 [inline]
>  set_track mm/kasan/common.c:77 [inline]
>  kasan_set_free_info mm/kasan/common.c:332 [inline]
>  __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:471
>  kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
>  __cache_free mm/slab.c:3425 [inline]
>  kmem_cache_free+0x81/0xf0 mm/slab.c:3693
>  mempool_free_slab+0x1d/0x30 mm/mempool.c:520
>  mempool_free+0xd5/0x350 mm/mempool.c:502
>  bio_put+0x38b/0x460 block/bio.c:255
>  mpage_end_io+0x2f5/0x330 fs/mpage.c:58
>  bio_endio+0x4ff/0x570 block/bio.c:1818
>  req_bio_endio block/blk-core.c:245 [inline]
>  blk_update_request+0x438/0x10d0 block/blk-core.c:1464
>  scsi_end_request+0x8c/0xa20 drivers/scsi/scsi_lib.c:579
>  scsi_io_completion+0x17c/0x1b80 drivers/scsi/scsi_lib.c:963
>  scsi_finish_command+0x3b3/0x560 drivers/scsi/scsi.c:228
>  scsi_softirq_done+0x289/0x310 drivers/scsi/scsi_lib.c:1477
>  blk_done_softirq+0x312/0x370 block/blk-softirq.c:37
>  __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:762

Looks like buffered read IO on a loopback device on an ext4 image
file, and something is being tripped over in the new ext4 direct IO
path.  Might be an iomap issue, might be an ext4 issue, but it looks
like the buffered read bio completion is running while the iov is
still being submitted...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: KASAN: use-after-free Read in iov_iter_alignment
  2019-12-02 21:10 ` Dave Chinner
@ 2019-12-02 23:11   ` Matthew Bobrowski
  0 siblings, 0 replies; 3+ messages in thread
From: Matthew Bobrowski @ 2019-12-02 23:11 UTC (permalink / raw)
  To: Dave Chinner
  Cc: syzbot, darrick.wong, hch, linux-fsdevel, linux-kernel,
	linux-xfs, syzkaller-bugs, linux-ext4

On Tue, Dec 03, 2019 at 08:10:37AM +1100, Dave Chinner wrote:
> [cc linux-ext4@vger.kernel.org - this is reported from the new ext4
> dio->iomap code]
> 
> On Mon, Dec 02, 2019 at 09:15:08AM -0800, syzbot wrote:
> > Hello,
> > 
> > syzbot found the following crash on:
> > 
> > HEAD commit:    b94ae8ad Merge tag 'seccomp-v5.5-rc1' of git://git.kernel...
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=135a8d7ae00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=c2e464ae414aee8c
> > dashboard link: https://syzkaller.appspot.com/bug?extid=bea68382bae9490e7dd6
> > compiler:       clang version 9.0.0 (/home/glider/llvm/clang
> > 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1135cb36e00000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14e90abce00000
> > 
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+bea68382bae9490e7dd6@syzkaller.appspotmail.com
> > 
> > ==================================================================
> > BUG: KASAN: use-after-free in iov_iter_alignment+0x6a1/0x7b0
> > lib/iov_iter.c:1225
> > Read of size 4 at addr ffff888098d40f54 by task loop0/8203
> > 
> > CPU: 0 PID: 8203 Comm: loop0 Not tainted 5.4.0-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > Google 01/01/2011
> > Call Trace:
> >  __dump_stack lib/dump_stack.c:77 [inline]
> >  dump_stack+0x1fb/0x318 lib/dump_stack.c:118
> >  print_address_description+0x75/0x5c0 mm/kasan/report.c:374
> >  __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
> >  kasan_report+0x26/0x50 mm/kasan/common.c:634
> >  __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
> >  iov_iter_alignment+0x6a1/0x7b0 lib/iov_iter.c:1225
> >  iomap_dio_bio_actor+0x1a7/0x11e0 fs/iomap/direct-io.c:203
> >  iomap_dio_actor+0x2b4/0x4a0 fs/iomap/direct-io.c:375
> >  iomap_apply+0x370/0x490 fs/iomap/apply.c:80
> >  iomap_dio_rw+0x8ad/0x1010 fs/iomap/direct-io.c:493
> >  ext4_dio_read_iter fs/ext4/file.c:77 [inline]
> >  ext4_file_read_iter+0x834/0xc20 fs/ext4/file.c:128
> >  lo_rw_aio+0xcbb/0xea0 include/linux/fs.h:1889
> 
> loopback -> ext4 direct IO, bad access on iov passed to iomap DIO
> code.
> 
> >  do_req_filebacked drivers/block/loop.c:616 [inline]
> >  loop_handle_cmd drivers/block/loop.c:1952 [inline]
> >  loop_queue_work+0x13ab/0x2590 drivers/block/loop.c:1966
> >  kthread_worker_fn+0x449/0x700 kernel/kthread.c:671
> >  loop_kthread_worker_fn+0x40/0x60 drivers/block/loop.c:901
> >  kthread+0x332/0x350 kernel/kthread.c:255
> >  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> > 
> > Allocated by task 4198:
> >  save_stack mm/kasan/common.c:69 [inline]
> >  set_track mm/kasan/common.c:77 [inline]
> >  __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:510
> >  kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:518
> >  slab_post_alloc_hook mm/slab.h:584 [inline]
> >  slab_alloc mm/slab.c:3319 [inline]
> >  kmem_cache_alloc+0x1f5/0x2e0 mm/slab.c:3483
> >  mempool_alloc_slab+0x4d/0x70 mm/mempool.c:513
> >  mempool_alloc+0x104/0x5e0 mm/mempool.c:393
> >  bio_alloc_bioset+0x1b0/0x5f0 block/bio.c:477
> >  bio_alloc include/linux/bio.h:400 [inline]
> >  mpage_alloc fs/mpage.c:79 [inline]
> >  do_mpage_readpage+0x1685/0x1d10 fs/mpage.c:306
> >  mpage_readpages+0x2a9/0x440 fs/mpage.c:404
> >  blkdev_readpages+0x2c/0x40 fs/block_dev.c:620
> >  read_pages+0xad/0x4d0 mm/readahead.c:126
> >  __do_page_cache_readahead+0x480/0x530 mm/readahead.c:212
> >  force_page_cache_readahead mm/readahead.c:243 [inline]
> >  page_cache_sync_readahead+0x329/0x3b0 mm/readahead.c:522
> >  generic_file_buffered_read+0x41d/0x2570 mm/filemap.c:2051
> >  generic_file_read_iter+0xa9/0x450 mm/filemap.c:2324
> >  blkdev_read_iter+0x12e/0x140 fs/block_dev.c:2039
> >  call_read_iter include/linux/fs.h:1889 [inline]
> >  new_sync_read fs/read_write.c:414 [inline]
> >  __vfs_read+0x59e/0x730 fs/read_write.c:427
> >  vfs_read+0x1dd/0x420 fs/read_write.c:461
> >  ksys_read+0x117/0x220 fs/read_write.c:587
> >  __do_sys_read fs/read_write.c:597 [inline]
> >  __se_sys_read fs/read_write.c:595 [inline]
> >  __x64_sys_read+0x7b/0x90 fs/read_write.c:595
> >  do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
> >  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> > 
> > Freed by task 4205:
> >  save_stack mm/kasan/common.c:69 [inline]
> >  set_track mm/kasan/common.c:77 [inline]
> >  kasan_set_free_info mm/kasan/common.c:332 [inline]
> >  __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:471
> >  kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
> >  __cache_free mm/slab.c:3425 [inline]
> >  kmem_cache_free+0x81/0xf0 mm/slab.c:3693
> >  mempool_free_slab+0x1d/0x30 mm/mempool.c:520
> >  mempool_free+0xd5/0x350 mm/mempool.c:502
> >  bio_put+0x38b/0x460 block/bio.c:255
> >  mpage_end_io+0x2f5/0x330 fs/mpage.c:58
> >  bio_endio+0x4ff/0x570 block/bio.c:1818
> >  req_bio_endio block/blk-core.c:245 [inline]
> >  blk_update_request+0x438/0x10d0 block/blk-core.c:1464
> >  scsi_end_request+0x8c/0xa20 drivers/scsi/scsi_lib.c:579
> >  scsi_io_completion+0x17c/0x1b80 drivers/scsi/scsi_lib.c:963
> >  scsi_finish_command+0x3b3/0x560 drivers/scsi/scsi.c:228
> >  scsi_softirq_done+0x289/0x310 drivers/scsi/scsi_lib.c:1477
> >  blk_done_softirq+0x312/0x370 block/blk-softirq.c:37
> >  __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:762
> 
> Looks like buffered read IO on a loopback device on an ext4 image
> file, and something is being tripped over in the new ext4 direct IO
> path.  Might be an iomap issue, might be an ext4 issue, but it looks
> like the buffered read bio completion is running while the iov is
> still being submitted...

Thanks Dave.

I will take a look at this when I get home this evening and see
whether I can pinpoint what's going on here...

/M

^ permalink raw reply	[flat|nested] 3+ messages in thread

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Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-12-02 17:15 KASAN: use-after-free Read in iov_iter_alignment syzbot
2019-12-02 21:10 ` Dave Chinner
2019-12-02 23:11   ` Matthew Bobrowski

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