kernel/linux.git/block/bdev.c, branch v5.15.212

block: Avoid mounting the bdev pseudo-filesystem in userspace

2026-07-24T13:51:17+00:00

[ Upstream commit f73aa66dffcb8e61e78f01b56163ec16a15d06d2 ] The bdev pseudo-filesystem is an internal kernel filesystem with which userspace should not interfere. Unregister it so that userspace cannot even attempt to mount it. This fixes a bug [1] that occurs when attempting to access files, because the system call move_mount() uses pointers declared in the inode_operations structure, which for the bdev pseudo-filesystem are always equal to 0. `inode->i_op = &empty_iops;` [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 23380067 P4D 23380067 PUD 23381067 PMD 0 Oops: 0010 [#1] PREEMPT SMP KASAN NOPTI CPU: 2 PID: 17125 Comm: syz-executor.0 Not tainted 6.1.155-syzkaller-00350-g84221fde2681 #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:0x0 Call Trace: lookup_open.isra.0+0x700/0x1180 fs/namei.c:3460 open_last_lookups fs/namei.c:3550 [inline] path_openat+0x953/0x2700 fs/namei.c:3780 do_filp_open+0x1c5/0x410 fs/namei.c:3810 do_sys_openat2+0x171/0x4d0 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x13c/0x1f0 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/all/20131010004732.GJ13318@ZenIV.linux.org.uk/T/# Cc: stable@vger.kernel.org Signed-off-by: Denis Arefev Reviewed-by: Christoph Hellwig Link: https://patch.msgid.link/20260521072857.5078-1-arefev@swemel.ru Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

block: default BLOCK_LEGACY_AUTOLOAD to y

2025-06-27T10:05:34+00:00

commit 451f0b6f4c44d7b649ae609157b114b71f6d7875 upstream. As Luis reported, losetup currently doesn't properly create the loop device without this if the device node already exists because old scripts created it manually. So default to y for now and remove the aggressive removal schedule. Reported-by: Luis Chamberlain Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20220225181440.1351591-1-hch@lst.de Signed-off-by: Jens Axboe Cc: Sebastian Priebe Link: https://lore.kernel.org/r/ZR0P278MB097497EF6CFD85E72819447E9F70A@ZR0P278MB0974.CHEP278.PROD.OUTLOOK.COM Signed-off-by: Greg Kroah-Hartman

block: deprecate autoloading based on dev_t

2025-03-13T11:49:51+00:00

[ Upstream commit fbdee71bb5d8d054e1bdb5af4c540f2cb86fe296 ] Make the legacy dev_t based autoloading optional and add a deprecation warning. This kind of autoloading has ceased to be useful about 20 years ago. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220104071647.164918-1-hch@lst.de Signed-off-by: Jens Axboe Stable-dep-of: 457ef47c08d2 ("block: retry call probe after request_module in blk_request_module") Signed-off-by: Sasha Levin

block: move GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE to disk->event_flags

2023-09-19T10:23:02+00:00

[ Upstream commit 1545e0b419ba1d9b9bee4061d4826340afe6b0aa ] GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE is all about the event reporting mechanism, so move it to the event_flags field. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211122130625.1136848-3-hch@lst.de Signed-off-by: Jens Axboe Stable-dep-of: 1a721de8489f ("block: don't add or resize partition on the disk with GENHD_FL_NO_PART") Signed-off-by: Sasha Levin

block: simplify the block device syncing code

2022-04-27T12:38:50+00:00

[ Upstream commit 1e03a36bdff4709c1bbf0f57f60ae3f776d51adf ] Get rid of the indirections and just provide a sync_bdevs helper for the generic sync code. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211019062530.2174626-8-hch@lst.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: remove __sync_blockdev

2022-04-27T12:38:50+00:00

[ Upstream commit 70164eb6ccb76ab679b016b4b60123bf4ec6c162 ] Instead offer a new sync_blockdev_nowait helper for the !wait case. This new helper is exported as it will grow modular callers in a bit. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211019062530.2174626-3-hch@lst.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: genhd: fix double kfree() in __alloc_disk_node()

2021-10-02T13:29:20+00:00

syzbot is reporting use-after-free read at bdev_free_inode() [1], for kfree() from __alloc_disk_node() is called before bdev_free_inode() (which is called after RCU grace period) reads bdev->bd_disk and calls kfree(bdev->bd_disk). Fix use-after-free read followed by double kfree() problem by making sure that bdev->bd_disk is NULL when calling iput(). Link: https://syzkaller.appspot.com/bug?extid=8281086e8a6fbfbd952a [1] Reported-by: syzbot Signed-off-by: Tetsuo Handa Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/e6dd13c5-8db0-4392-6e78-a42ee5d2a1c4@i-love.sakura.ne.jp Signed-off-by: Jens Axboe

block: move fs/block_dev.c to block/bdev.c

2021-09-07T14:39:40+00:00

Move it together with the rest of the block layer. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210907141303.1371844-3-hch@lst.de Signed-off-by: Jens Axboe