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Jiufei Xue authored
We see the following NULL pointer dereference while running xfstests generic/475: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 PGD 8000000c84bad067 P4D 8000000c84bad067 PUD c84e62067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 7 PID: 9886 Comm: fsstress Kdump: loaded Not tainted 5.0.0-rc8 #10 RIP: 0010:ext4_do_update_inode+0x4ec/0x760 ... Call Trace: ? jbd2_journal_get_write_access+0x42/0x50 ? __ext4_journal_get_write_access+0x2c/0x70 ? ext4_truncate+0x186/0x3f0 ext4_mark_iloc_dirty+0x61/0x80 ext4_mark_inode_dirty+0x62/0x1b0 ext4_truncate+0x186/0x3f0 ? unmap_mapping_pages+0x56/0x100 ext4_setattr+0x817/0x8b0 notify_change+0x1df/0x430 do_truncate+0x5e/0x90 ? generic_permission+0x12b/0x1a0 This is triggered because the NULL pointer handle->h_transaction was dereferenced in function ext4_update_inode_fsync_trans(). I found that the h_transaction was set to NULL in jbd2__journal_restart but failed to attached to a new transaction while the journal is aborted. Fix this by checking the handle before updating the inode. Fixes: b436b9be ("ext4: Wait for proper transaction commit on fsync") Signed-off-by:
Jiufei Xue <jiufei.xue@linux.alibaba.com> Signed-off-by:
Theodore Ts'o <tytso@mit.edu> Reviewed-by:
Joseph Qi <joseph.qi@linux.alibaba.com> Cc: stable@kernel.org
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