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authorRoman Gushchin <guro@fb.com>2021-07-23 15:50:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-07-23 17:43:28 -0700
commit593311e85b26ecc6e4d45b6fb81b942b6672df09 (patch)
treec37d0efb8f03d42f2dd022f4846c847c5d236cca /fs/fs-writeback.c
parentb43a9e76b4cc78cdaa8c809dd31cd452797b7661 (diff)
writeback, cgroup: do not reparent dax inodes
The inode switching code is not suited for dax inodes. An attempt to switch a dax inode to a parent writeback structure (as a part of a writeback cleanup procedure) results in a panic like this: run fstests generic/270 at 2021-07-15 05:54:02 XFS (pmem0p2): EXPERIMENTAL big timestamp feature in use. Use at your own risk! XFS (pmem0p2): DAX enabled. Warning: EXPERIMENTAL, use at your own risk XFS (pmem0p2): EXPERIMENTAL inode btree counters feature in use. Use at your own risk! XFS (pmem0p2): Mounting V5 Filesystem XFS (pmem0p2): Ending clean mount XFS (pmem0p2): Quotacheck needed: Please wait. XFS (pmem0p2): Quotacheck: Done. XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks) XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks) XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks) BUG: unable to handle page fault for address: 0000000005b0f669 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 13 PID: 10479 Comm: kworker/13:16 Not tainted 5.14.0-rc1-master-8096acd7442e+ #8 Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 09/13/2016 Workqueue: inode_switch_wbs inode_switch_wbs_work_fn RIP: 0010:inode_do_switch_wbs+0xaf/0x470 Code: 00 30 0f 85 c1 03 00 00 0f 1f 44 00 00 31 d2 48 c7 c6 ff ff ff ff 48 8d 7c 24 08 e8 eb 49 1a 00 48 85 c0 74 4a bb ff ff ff ff <48> 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 00 a8 08 0f 85 RSP: 0018:ffff9c66691abdc8 EFLAGS: 00010002 RAX: 0000000005b0f661 RBX: 00000000ffffffff RCX: ffff89e6a21382b0 RDX: 0000000000000001 RSI: ffff89e350230248 RDI: ffffffffffffffff RBP: ffff89e681d19400 R08: 0000000000000000 R09: 0000000000000228 R10: ffffffffffffffff R11: ffffffffffffffc0 R12: ffff89e6a2138130 R13: ffff89e316af7400 R14: ffff89e316af6e78 R15: ffff89e6a21382b0 FS: 0000000000000000(0000) GS:ffff89ee5fb40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000005b0f669 CR3: 0000000cb2410004 CR4: 00000000001706e0 Call Trace: inode_switch_wbs_work_fn+0xb6/0x2a0 process_one_work+0x1e6/0x380 worker_thread+0x53/0x3d0 kthread+0x10f/0x130 ret_from_fork+0x22/0x30 Modules linked in: xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nft_counter nf_tables nfnetlink bridge stp llc rfkill sunrpc intel_rapl_msr intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel ipmi_ssif kvm mgag200 i2c_algo_bit iTCO_wdt irqbypass drm_kms_helper iTCO_vendor_support acpi_ipmi rapl syscopyarea sysfillrect intel_cstate ipmi_si sysimgblt ioatdma dax_pmem_compat fb_sys_fops ipmi_devintf device_dax i2c_i801 pcspkr intel_uncore hpilo nd_pmem cec dax_pmem_core dca i2c_smbus acpi_tad lpc_ich ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sd_mod t10_pi crct10dif_pclmul crc32_pclmul crc32c_intel tg3 ghash_clmulni_intel serio_raw hpsa hpwdt scsi_transport_sas wmi dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000005b0f669 ---[ end trace ed2105faff8384f3 ]--- RIP: 0010:inode_do_switch_wbs+0xaf/0x470 Code: 00 30 0f 85 c1 03 00 00 0f 1f 44 00 00 31 d2 48 c7 c6 ff ff ff ff 48 8d 7c 24 08 e8 eb 49 1a 00 48 85 c0 74 4a bb ff ff ff ff <48> 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 00 a8 08 0f 85 RSP: 0018:ffff9c66691abdc8 EFLAGS: 00010002 RAX: 0000000005b0f661 RBX: 00000000ffffffff RCX: ffff89e6a21382b0 RDX: 0000000000000001 RSI: ffff89e350230248 RDI: ffffffffffffffff RBP: ffff89e681d19400 R08: 0000000000000000 R09: 0000000000000228 R10: ffffffffffffffff R11: ffffffffffffffc0 R12: ffff89e6a2138130 R13: ffff89e316af7400 R14: ffff89e316af6e78 R15: ffff89e6a21382b0 FS: 0000000000000000(0000) GS:ffff89ee5fb40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000005b0f669 CR3: 0000000cb2410004 CR4: 00000000001706e0 Kernel panic - not syncing: Fatal exception Kernel Offset: 0x15200000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception ]--- The crash happens on an attempt to iterate over attached pagecache pages and check the dirty flag: a dax inode's xarray contains pfn's instead of generic struct page pointers. This happens for DAX and not for other kinds of non-page entries in the inodes because it's a tagged iteration, and shadow/swap entries are never tagged; only DAX entries get tagged. Fix the problem by bailing out (with the false return value) of inode_prepare_sbs_switch() if a dax inode is passed. [willy@infradead.org: changelog addition] Link: https://lkml.kernel.org/r/20210719171350.3876830-1-guro@fb.com Fixes: c22d70a162d3 ("writeback, cgroup: release dying cgwbs by switching attached inodes") Signed-off-by: Roman Gushchin <guro@fb.com> Reported-by: Murphy Zhou <jencce.kernel@gmail.com> Reported-by: Darrick J. Wong <djwong@kernel.org> Tested-by: Darrick J. Wong <djwong@kernel.org> Tested-by: Murphy Zhou <jencce.kernel@gmail.com> Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Jan Kara <jack@suse.cz> Cc: Dave Chinner <dchinner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 06d04a74ab6c..4c3370548982 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -521,6 +521,9 @@ static bool inode_prepare_wbs_switch(struct inode *inode,
*/
smp_mb();
+ if (IS_DAX(inode))
+ return false;
+
/* while holding I_WB_SWITCH, no one else can update the association */
spin_lock(&inode->i_lock);
if (!(inode->i_sb->s_flags & SB_ACTIVE) ||