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0b438c5bfa
This fixes the following bug: Journal reclaim attempts to flush a node, but races with the node being evicted from the btree node cache; when we lock the node, the data buffers have already been freed. We don't evict a node that's dirty, so calling btree_node_write() is fine - it's a noop - except that the btree_node_just_written bit causes bch2_btree_post_write_cleanup() to run (resorting the node), which then causes a null ptr deref. 00078 Unable to handle kernel NULL pointer dereference at virtual address 000000000000009e 00078 Mem abort info: 00078 ESR = 0x0000000096000005 00078 EC = 0x25: DABT (current EL), IL = 32 bits 00078 SET = 0, FnV = 0 00078 EA = 0, S1PTW = 0 00078 FSC = 0x05: level 1 translation fault 00078 Data abort info: 00078 ISV = 0, ISS = 0x00000005 00078 CM = 0, WnR = 0 00078 user pgtable: 4k pages, 39-bit VAs, pgdp=000000007ed64000 00078 [000000000000009e] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000 00078 Internal error: Oops: 0000000096000005 [#1] SMP 00078 Modules linked in: 00078 CPU: 75 PID: 1170 Comm: stress-ng-utime Not tainted 6.3.0-ktest-g5ef5b466e77e #2078 00078 Hardware name: linux,dummy-virt (DT) 00078 pstate: 80001005 (Nzcv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=--) 00078 pc : btree_node_sort+0xc4/0x568 00078 lr : bch2_btree_post_write_cleanup+0x6c/0x1c0 00078 sp : ffffff803e30b350 00078 x29: ffffff803e30b350 x28: 0000000000000001 x27: ffffff80076e52a8 00078 x26: 0000000000000002 x25: 0000000000000000 x24: ffffffc00912e000 00078 x23: ffffff80076e52a8 x22: 0000000000000000 x21: ffffff80076e52bc 00078 x20: ffffff80076e5200 x19: 0000000000000000 x18: 0000000000000000 00078 x17: fffffffff8000000 x16: 0000000008000000 x15: 0000000008000000 00078 x14: 0000000000000002 x13: 0000000000000000 x12: 00000000000000a0 00078 x11: ffffff803e30b400 x10: ffffff803e30b408 x9 : 0000000000000001 00078 x8 : 0000000000000000 x7 : ffffff803e480000 x6 : 00000000000000a0 00078 x5 : 0000000000000088 x4 : 0000000000000000 x3 : 0000000000000010 00078 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffff80076e52a8 00078 Call trace: 00078 btree_node_sort+0xc4/0x568 00078 bch2_btree_post_write_cleanup+0x6c/0x1c0 00078 bch2_btree_node_write+0x108/0x148 00078 __btree_node_flush+0x104/0x160 00078 bch2_btree_node_flush0+0x1c/0x30 00078 journal_flush_pins.constprop.0+0x184/0x2d0 00078 __bch2_journal_reclaim+0x4d4/0x508 00078 bch2_journal_reclaim+0x1c/0x30 00078 __bch2_journal_preres_get+0x244/0x268 00078 bch2_trans_journal_preres_get_cold+0xa4/0x180 00078 __bch2_trans_commit+0x61c/0x1bb0 00078 bch2_setattr_nonsize+0x254/0x318 00078 bch2_setattr+0x5c/0x78 00078 notify_change+0x2bc/0x408 00078 vfs_utimes+0x11c/0x218 00078 do_utimes+0x84/0x140 00078 __arm64_sys_utimensat+0x68/0xa8 00078 invoke_syscall.constprop.0+0x54/0xf0 00078 do_el0_svc+0x48/0xd8 00078 el0_svc+0x14/0x48 00078 el0t_64_sync_handler+0xb0/0xb8 00078 el0t_64_sync+0x14c/0x150 00078 Code: 8b050265 910020c6 8b060266 910060ac (79402cad) 00078 ---[ end trace 0000000000000000 ]--- Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.