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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	syzbot+a70e2ad0879f160b9217@syzkaller.appspotmail.com,
	Anand Jain <anand.jain@oracle.com>,
	Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
	David Sterba <dsterba@suse.com>
Subject: [PATCH 5.10 04/67] btrfs: fix rw device counting in __btrfs_free_extra_devids
Date: Mon,  2 Aug 2021 15:44:27 +0200	[thread overview]
Message-ID: <20210802134339.169496491@linuxfoundation.org> (raw)
In-Reply-To: <20210802134339.023067817@linuxfoundation.org>

From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>

commit b2a616676839e2a6b02c8e40be7f886f882ed194 upstream.

When removing a writeable device in __btrfs_free_extra_devids, the rw
device count should be decremented.

This error was caught by Syzbot which reported a warning in
close_fs_devices:

  WARNING: CPU: 1 PID: 9355 at fs/btrfs/volumes.c:1168 close_fs_devices+0x763/0x880 fs/btrfs/volumes.c:1168
  Modules linked in:
  CPU: 0 PID: 9355 Comm: syz-executor552 Not tainted 5.13.0-rc1-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  RIP: 0010:close_fs_devices+0x763/0x880 fs/btrfs/volumes.c:1168
  RSP: 0018:ffffc9000333f2f0 EFLAGS: 00010293
  RAX: ffffffff8365f5c3 RBX: 0000000000000001 RCX: ffff888029afd4c0
  RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
  RBP: ffff88802846f508 R08: ffffffff8365f525 R09: ffffed100337d128
  R10: ffffed100337d128 R11: 0000000000000000 R12: dffffc0000000000
  R13: ffff888019be8868 R14: 1ffff1100337d10d R15: 1ffff1100337d10a
  FS:  00007f6f53828700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000000000047c410 CR3: 00000000302a6000 CR4: 00000000001506f0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   btrfs_close_devices+0xc9/0x450 fs/btrfs/volumes.c:1180
   open_ctree+0x8e1/0x3968 fs/btrfs/disk-io.c:3693
   btrfs_fill_super fs/btrfs/super.c:1382 [inline]
   btrfs_mount_root+0xac5/0xc60 fs/btrfs/super.c:1749
   legacy_get_tree+0xea/0x180 fs/fs_context.c:592
   vfs_get_tree+0x86/0x270 fs/super.c:1498
   fc_mount fs/namespace.c:993 [inline]
   vfs_kern_mount+0xc9/0x160 fs/namespace.c:1023
   btrfs_mount+0x3d3/0xb50 fs/btrfs/super.c:1809
   legacy_get_tree+0xea/0x180 fs/fs_context.c:592
   vfs_get_tree+0x86/0x270 fs/super.c:1498
   do_new_mount fs/namespace.c:2905 [inline]
   path_mount+0x196f/0x2be0 fs/namespace.c:3235
   do_mount fs/namespace.c:3248 [inline]
   __do_sys_mount fs/namespace.c:3456 [inline]
   __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433
   do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Because fs_devices->rw_devices was not 0 after
closing all devices. Here is the call trace that was observed:

  btrfs_mount_root():
    btrfs_scan_one_device():
      device_list_add();   <---------------- device added
    btrfs_open_devices():
      open_fs_devices():
        btrfs_open_one_device();   <-------- writable device opened,
	                                     rw device count ++
    btrfs_fill_super():
      open_ctree():
        btrfs_free_extra_devids():
	  __btrfs_free_extra_devids();  <--- writable device removed,
	                              rw device count not decremented
	  fail_tree_roots:
	    btrfs_close_devices():
	      close_fs_devices();   <------- rw device count off by 1

As a note, prior to commit cf89af146b7e ("btrfs: dev-replace: fail
mount if we don't have replace item with target device"), rw_devices
was decremented on removing a writable device in
__btrfs_free_extra_devids only if the BTRFS_DEV_STATE_REPLACE_TGT bit
was not set for the device. However, this check does not need to be
reinstated as it is now redundant and incorrect.

In __btrfs_free_extra_devids, we skip removing the device if it is the
target for replacement. This is done by checking whether device->devid
== BTRFS_DEV_REPLACE_DEVID. Since BTRFS_DEV_STATE_REPLACE_TGT is set
only on the device with devid BTRFS_DEV_REPLACE_DEVID, no devices
should have the BTRFS_DEV_STATE_REPLACE_TGT bit set after the check,
and so it's redundant to test for that bit.

Additionally, following commit 82372bc816d7 ("Btrfs: make
the logic of source device removing more clear"), rw_devices is
incremented whenever a writeable device is added to the alloc
list (including the target device in btrfs_dev_replace_finishing), so
all removals of writable devices from the alloc list should also be
accompanied by a decrement to rw_devices.

Reported-by: syzbot+a70e2ad0879f160b9217@syzkaller.appspotmail.com
Fixes: cf89af146b7e ("btrfs: dev-replace: fail mount if we don't have replace item with target device")
CC: stable@vger.kernel.org # 5.10+
Tested-by: syzbot+a70e2ad0879f160b9217@syzkaller.appspotmail.com
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/btrfs/volumes.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1077,6 +1077,7 @@ static void __btrfs_free_extra_devids(st
 		if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
 			list_del_init(&device->dev_alloc_list);
 			clear_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
+			fs_devices->rw_devices--;
 		}
 		list_del_init(&device->dev_list);
 		fs_devices->num_devices--;



  parent reply	other threads:[~2021-08-02 14:00 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 13:44 [PATCH 5.10 00/67] 5.10.56-rc1 review Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 01/67] io_uring: fix null-ptr-deref in io_sq_offload_start() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 02/67] x86/asm: Ensure asm/proto.h can be included stand-alone Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 03/67] pipe: make pipe writes always wake up readers Greg Kroah-Hartman
2021-08-02 13:44 ` Greg Kroah-Hartman [this message]
2021-08-02 13:44 ` [PATCH 5.10 05/67] btrfs: mark compressed range uptodate only if all bio succeed Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 06/67] Revert "ACPI: resources: Add checks for ACPI IRQ override" Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 07/67] ACPI: DPTF: Fix reading of attributes Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 08/67] x86/kvm: fix vcpu-id indexed array sizes Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 09/67] KVM: add missing compat KVM_CLEAR_DIRTY_LOG Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 10/67] ocfs2: fix zero out valid data Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 11/67] ocfs2: issue zeroout to EOF blocks Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 12/67] can: j1939: j1939_xtp_rx_dat_one(): fix rxtimer value between consecutive TP.DT to 750ms Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 13/67] can: raw: raw_setsockopt(): fix raw_rcv panic for sock UAF Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 14/67] can: peak_usb: pcan_usb_handle_bus_evt(): fix reading rxerr/txerr values Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 15/67] can: mcba_usb_start(): add missing urb->transfer_dma initialization Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 16/67] can: usb_8dev: fix memory leak Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 17/67] can: ems_usb: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 18/67] can: esd_usb2: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 19/67] alpha: register early reserved memory in memblock Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 20/67] HID: wacom: Re-enable touch by default for Cintiq 24HDT / 27QHDT Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 21/67] NIU: fix incorrect error return, missed in previous revert Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 22/67] drm/amd/display: ensure dentist display clock update finished in DCN20 Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 23/67] drm/amdgpu: Avoid printing of stack contents on firmware load error Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 24/67] drm/amdgpu: Fix resource leak on probe error path Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 25/67] blk-iocost: fix operation ordering in iocg_wake_fn() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 26/67] nfc: nfcsim: fix use after free during module unload Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 27/67] cfg80211: Fix possible memory leak in function cfg80211_bss_update Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 28/67] RDMA/bnxt_re: Fix stats counters Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 29/67] bpf: Fix OOB read when printing XDP link fdinfo Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 30/67] mac80211: fix enabling 4-address mode on a sta vif after assoc Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 31/67] netfilter: conntrack: adjust stop timestamp to real expiry value Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 32/67] netfilter: nft_nat: allow to specify layer 4 protocol NAT only Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 33/67] i40e: Fix logic of disabling queues Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 34/67] i40e: Fix firmware LLDP agent related warning Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 35/67] i40e: Fix queue-to-TC mapping on Tx Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 5.10 36/67] i40e: Fix log TC creation failure when max num of queues is exceeded Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 37/67] tipc: fix implicit-connect for SYN+ Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 38/67] tipc: fix sleeping in tipc accept routine Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 39/67] net: Set true network header for ECN decapsulation Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 40/67] net: qrtr: fix memory leaks Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 41/67] ionic: remove intr coalesce update from napi Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 42/67] ionic: fix up dim accounting for tx and rx Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 43/67] ionic: count csum_none when offload enabled Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 44/67] tipc: do not write skb_shinfo frags when doing decrytion Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 45/67] octeontx2-pf: Fix interface down flag on error Greg Kroah-Hartman
2021-08-02 17:40   ` Pavel Machek
2021-08-02 13:45 ` [PATCH 5.10 46/67] mlx4: Fix missing error code in mlx4_load_one() Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 47/67] KVM: x86: Check the right feature bit for MSR_KVM_ASYNC_PF_ACK access Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 48/67] net: llc: fix skb_over_panic Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 49/67] drm/msm/dpu: Fix sm8250_mdp register length Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 50/67] drm/msm/dp: Initialize the INTF_CONFIG register Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 51/67] skmsg: Make sk_psock_destroy() static Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 52/67] net/mlx5: Fix flow table chaining Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 53/67] net/mlx5e: Fix nullptr in mlx5e_hairpin_get_mdev() Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 54/67] sctp: fix return value check in __sctp_rcv_asconf_lookup Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 55/67] tulip: windbond-840: Fix missing pci_disable_device() in probe and remove Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 56/67] sis900: " Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 57/67] can: hi311x: fix a signedness bug in hi3110_cmd() Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 58/67] bpf: Introduce BPF nospec instruction for mitigating Spectre v4 Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 59/67] bpf: Fix leakage due to insufficient speculative store bypass mitigation Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 60/67] bpf: Remove superfluous aux sanitation on subprog rejection Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 61/67] bpf: verifier: Allocate idmap scratch in verifier env Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 62/67] bpf: Fix pointer arithmetic mask tightening under state pruning Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 63/67] SMB3: fix readpage for large swap cache Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 64/67] powerpc/pseries: Fix regression while building external modules Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 65/67] Revert "perf map: Fix dso->nsinfo refcounting" Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 66/67] i40e: Add additional info to PHY type error Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 5.10 67/67] can: j1939: j1939_session_deactivate(): clarify lifetime of session object Greg Kroah-Hartman
2021-08-02 16:23 ` [PATCH 5.10 00/67] 5.10.56-rc1 review Fox Chen
2021-08-02 17:49 ` Pavel Machek
2021-08-03  7:23 ` Naresh Kamboju
2021-08-03 10:38 ` Sudip Mukherjee
2021-08-03 11:13 ` Rudi Heitbaum
2021-08-03 19:16 ` Guenter Roeck
2021-08-03 19:26 ` Pavel Machek
2021-08-03 19:37   ` Guenter Roeck
2021-08-03 19:50     ` Pavel Machek
2021-08-03 20:52       ` Guenter Roeck
2021-08-04  6:21   ` Greg Kroah-Hartman
2021-08-04  6:25   ` Thomas Backlund
2021-08-04  6:35     ` Greg Kroah-Hartman
2021-08-04  3:05 ` Samuel Zou

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