From: David Howells <dhowells@redhat.com>
To: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@infradead.org>
Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: dhowells@redhat.com
Subject: Is there a reason why REQ_OP_READ has to be 0?
Date: Mon, 16 Jan 2023 16:01:50 +0000 [thread overview]
Message-ID: <2117829.1673884910@warthog.procyon.org.uk> (raw)
Hi Jens, Christoph,
Do you know if there's a reason why REQ_OP_READ has to be 0? I'm seeing a
circumstance where a direct I/O write on a blockdev is BUG'ing in my modified
iov_iter code because the iterator says it's a source iterator (correct), but
the bio->bi_opf == REQ_OP_READ (which should be wrong).
I thought I'd move REQ_OP_READ to, say, 4 so that I could try and see if it's
just undefined but the kernel BUGs and then panics during boot.
David
------------[ cut here ]------------
kernel BUG at mm/filemap.c:1615!
------------[ cut here ]------------
invalid opcode: 0000 [#1] PREEMPT SMP PTI
kernel BUG at mm/filemap.c:1615!
CPU: 1 PID: 2196 Comm: systemd-udevd Not tainted 6.2.0-rc2-build3+ #12783
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
RIP: 0010:folio_end_writeback+0x30/0x70
Code: 48 8b 07 48 89 fb 0f ba e0 12 73 0a f0 80 67 02 fb e8 d0 de 00 00 48 89 df e8 fe df ff ff 48 89 df e8 f9 ac 00 00 84 c0 75 02 <0f> 0b 48 8b 03 84 c0 79 0d be 0f 00 00 00 48 89 df e8 44 f3 ff ff
RSP: 0000:ffff8881091a3db8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffea0004271d40 RCX: 0000000000001000
RDX: 0000000000000101 RSI: 0000000000000246 RDI: ffff888107694000
RBP: ffff888100b6f600 R08: 000000204d567e99 R09: 0000000000000200
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000001000 R15: ffff888107402080
FS: 00007f65ecde8940(0000) GS:ffff88840fa80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb269292ba1 CR3: 0000000107140004 CR4: 00000000001706e0
Call Trace:
<TASK>
mpage_end_io+0x91/0x9b
blk_update_request+0x200/0x2be
scsi_end_request+0x27/0xf3
scsi_io_completion+0x151/0x21e
blk_complete_reqs+0x41/0x4c
__do_softirq+0x123/0x27d
__irq_exit_rcu+0x5a/0xcd
common_interrupt+0x36/0xbc
asm_common_interrupt+0x22/0x40
RIP: 0033:0x7f65edc7ab60
Code: 00 41 29 c5 4a 8d 14 ed 00 00 00 00 49 8d 34 0c 49 8d 7c 0c f8 e8 d0 5e ff ff 83 6d 20 01 eb 9f 66 2e 0f 1f 84 00 00 00 00 00 <f3> 0f 1e fa 53 48 89 fb 48 83 c7 08 e8 7f 60 ff ff 85 c0 75 0b 48
RSP: 002b:00007ffe0b70bd88 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 000055ddc430c5dc RCX: 000055ddc4301f98
RDX: 00000000000000ff RSI: 000000000000000c RDI: 000055ddc4301f98
RBP: 00007ffe0b7102d0 R08: 45d54cec8b358fc3 R09: 00544145535f4449
R10: 000000000000000c R11: f17eedd8cae0d043 R12: 000055ddc4302920
R13: 000055ddc432091a R14: 000055ddc4308460 R15: 000055ddc42d90dc
</TASK>
Modules linked in:
invalid opcode: 0000 [#2] PREEMPT SMP PTI
next reply other threads:[~2023-01-16 16:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-16 16:01 David Howells [this message]
2023-01-16 16:04 ` Is there a reason why REQ_OP_READ has to be 0? Christoph Hellwig
2023-01-16 16:06 ` Jens Axboe
2023-01-16 16:17 ` David Howells
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2117829.1673884910@warthog.procyon.org.uk \
--to=dhowells@redhat.com \
--cc=axboe@kernel.dk \
--cc=hch@infradead.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox