tjh.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.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1444070
3
928
Clone this repository
https://tangled.org/tjh.dev/kernel
https://tangled.org/did:plc:65gha4t3avpfpzmvpbwovss7/kernel
git@gordian.tjh.dev:tjh.dev/kernel
git@gordian.tjh.dev:did:plc:65gha4t3avpfpzmvpbwovss7/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
The change to use dma_set_mask_and_coherent() incorrectly made a second
call with the 32 bit DMA mask value when the call with the 64 bit DMA mask
value succeeded.
Fixes: c22b332d811b ("scsi: csiostor: switch to generic DMA API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The change to use dma_set_mask_and_coherent() incorrectly made a second
call with the 32 bit DMA mask value when the call with the 64 bit DMA mask
value succeeded.
[mkp: fixed commit message]
Fixes: a69b080025ea ("scsi: bfa: use dma_set_mask_and_coherent")
Cc: <stable@vger.kernel.org>
Suggested-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The change to use dma_set_mask_and_coherent() incorrectly made a second
call with the 32 bit DMA mask value when the call with the 64 bit DMA mask
value succeeded.
[mkp: fixed subject]
Fixes: 3a21986f1a59 ("scsi: aic94xx: fully convert to the generic DMA API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The change to use dma_set_mask_and_coherent() incorrectly made a second
call with the 32 bit DMA mask value when the call with the 64 bit DMA mask
value succeeded.
Fixes: b1fa122930c4 ("scsi: 3w-sas: fully convert to the generic DMA API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The change to use dma_set_mask_and_coherent() incorrectly made a second
call with the 32 bit DMA mask value when the call with the 64 bit DMA mask
value succeeded.
Fixes: b000bced5739 ("scsi: 3w-9xxx: fully convert to the generic DMA API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The change to use dma_set_mask_and_coherent() incorrectly made a second
call with the 32 bit DMA mask value when the call with the 64 bit DMA mask
value succeeded. This resulted in NVMe/FC connections failing due to
corrupted data buffers, and various other SCSI/FCP I/O errors.
Fixes: f30e1bfd6154 ("scsi: lpfc: use dma_set_mask_and_coherent")
Cc: <stable@vger.kernel.org>
Suggested-by: Don Dutile <ddutile@redhat.com>
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Up to 4.12, __scsi_error_from_host_byte() would reset the host byte to
DID_OK for various cases including DID_NEXUS_FAILURE. Commit
2a842acab109 ("block: introduce new block status code type") replaced this
function with scsi_result_to_blk_status() and removed the host-byte
resetting code for the DID_NEXUS_FAILURE case. As the line
set_host_byte(cmd, DID_OK) was preserved for the other cases, I suppose
this was an editing mistake.
The fact that the host byte remains set after 4.13 is causing problems with
the sg_persist tool, which now returns success rather then exit status 24
when a RESERVATION CONFLICT error is encountered.
Fixes: 2a842acab109 "block: introduce new block status code type"
Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The sysfs phy_identifier attribute for a sas_end_device comes from the rphy
phy_identifier value.
Currently this is not being set for rphys with an end device attached, so
we see incorrect symlinks from systemd disk/by-path:
root@localhost:~# ls -l /dev/disk/by-path/
total 0
lrwxrwxrwx 1 root root 9 Feb 13 12:26 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy0-lun-0 -> ../../sdb
lrwxrwxrwx 1 root root 10 Feb 13 12:26 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy0-lun-0-part1 -> ../../sdb1
lrwxrwxrwx 1 root root 10 Feb 13 12:26 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy0-lun-0-part2 -> ../../sdb2
lrwxrwxrwx 1 root root 10 Feb 13 12:26 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy0-lun-0-part3 -> ../../sdc3
Indeed, each sas_end_device phy_identifier value is 0:
root@localhost:/# more sys/class/sas_device/end_device-0\:0\:2/phy_identifier
0
root@localhost:/# more sys/class/sas_device/end_device-0\:0\:10/phy_identifier
0
This patch fixes the discovery code to set the phy_identifier. With this,
we now get proper symlinks:
root@localhost:~# ls -l /dev/disk/by-path/
total 0
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy10-lun-0 -> ../../sdg
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy11-lun-0 -> ../../sdh
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy2-lun-0 -> ../../sda
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy2-lun-0-part1 -> ../../sda1
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy3-lun-0 -> ../../sdb
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy3-lun-0-part1 -> ../../sdb1
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy3-lun-0-part2 -> ../../sdb2
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy4-lun-0 -> ../../sdc
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy4-lun-0-part1 -> ../../sdc1
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy4-lun-0-part2 -> ../../sdc2
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy4-lun-0-part3 -> ../../sdc3
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy5-lun-0 -> ../../sdd
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy7-lun-0 -> ../../sde
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy7-lun-0-part1 -> ../../sde1
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy7-lun-0-part2 -> ../../sde2
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy7-lun-0-part3 -> ../../sde3
lrwxrwxrwx 1 root root 9 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy8-lun-0 -> ../../sdf
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy8-lun-0-part1 -> ../../sdf1
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy8-lun-0-part2 -> ../../sdf2
lrwxrwxrwx 1 root root 10 Feb 13 11:53 platform-HISI0162:01-sas-exp0x500e004aaaaaaa1f-phy8-lun-0-part3 -> ../../sdf3
Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver")
Reported-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Tested-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The function sd_zbc_do_report_zones() issues a REPORT ZONES command with a
buffer size calculated based on the number of zones requested by the
caller. This value should however not exceed the capabilities of the
hardware maximum command size, that is, should not exceed the
max_hw_sectors limit of the device. This problem leads to failures of
report zones commands when re-validating disks with some SAS HBAs.
Fix this by limiting a report zone command buffer size to the minimum of
the device max_hw_sectors and calculated value based on the requested
number of zones. This does not change the semantic of the report_zones file
operation as report zones can always return less zone reports than
requested. Short reports are handled using a loop execution of the
report_zones file operation in the function blk_report_zones().
[Damien]
Before patch 'e76239a3748c ("block: add a report_zones method")', report
zones buffer allocation was limited to max_sectors when allocated in
blk_report_zones(). This however does not consider the actual format of the
device reply which is interface dependent. Limiting the allocation based
on the size of the expected reply format rather than the size of the array
of generic sturct blkzone passed by blk_report_zones() makes more sense.
Fixes: e76239a3748c ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Signed-off-by: Masato Suzuki <masato.suzuki@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
When a target sends Check Condition, whilst initiator is busy xmiting
re-queued data, could lead to race between iscsi_complete_task() and
iscsi_xmit_task() and eventually crashing with the following kernel
backtrace.
[3326150.987523] ALERT: BUG: unable to handle kernel NULL pointer dereference at 0000000000000078
[3326150.987549] ALERT: IP: [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi]
[3326150.987571] WARN: PGD 569c8067 PUD 569c9067 PMD 0
[3326150.987582] WARN: Oops: 0002 [#1] SMP
[3326150.987593] WARN: Modules linked in: tun nfsv3 nfs fscache dm_round_robin
[3326150.987762] WARN: CPU: 2 PID: 8399 Comm: kworker/u32:1 Tainted: G O 4.4.0+2 #1
[3326150.987774] WARN: Hardware name: Dell Inc. PowerEdge R720/0W7JN5, BIOS 2.5.4 01/22/2016
[3326150.987790] WARN: Workqueue: iscsi_q_13 iscsi_xmitworker [libiscsi]
[3326150.987799] WARN: task: ffff8801d50f3800 ti: ffff8801f5458000 task.ti: ffff8801f5458000
[3326150.987810] WARN: RIP: e030:[<ffffffffa05ce70d>] [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi]
[3326150.987825] WARN: RSP: e02b:ffff8801f545bdb0 EFLAGS: 00010246
[3326150.987831] WARN: RAX: 00000000ffffffc3 RBX: ffff880282d2ab20 RCX: ffff88026b6ac480
[3326150.987842] WARN: RDX: 0000000000000000 RSI: 00000000fffffe01 RDI: ffff880282d2ab20
[3326150.987852] WARN: RBP: ffff8801f545bdc8 R08: 0000000000000000 R09: 0000000000000008
[3326150.987862] WARN: R10: 0000000000000000 R11: 000000000000fe88 R12: 0000000000000000
[3326150.987872] WARN: R13: ffff880282d2abe8 R14: ffff880282d2abd8 R15: ffff880282d2ac08
[3326150.987890] WARN: FS: 00007f5a866b4840(0000) GS:ffff88028a640000(0000) knlGS:0000000000000000
[3326150.987900] WARN: CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033
[3326150.987907] WARN: CR2: 0000000000000078 CR3: 0000000070244000 CR4: 0000000000042660
[3326150.987918] WARN: Stack:
[3326150.987924] WARN: ffff880282d2ad58 ffff880282d2ab20 ffff880282d2abe8 ffff8801f545be18
[3326150.987938] WARN: ffffffffa05cea90 ffff880282d2abf8 ffff88026b59cc80 ffff88026b59cc00
[3326150.987951] WARN: ffff88022acf32c0 ffff880289491800 ffff880255a80800 0000000000000400
[3326150.987964] WARN: Call Trace:
[3326150.987975] WARN: [<ffffffffa05cea90>] iscsi_xmitworker+0x2f0/0x360 [libiscsi]
[3326150.987988] WARN: [<ffffffff8108862c>] process_one_work+0x1fc/0x3b0
[3326150.987997] WARN: [<ffffffff81088f95>] worker_thread+0x2a5/0x470
[3326150.988006] WARN: [<ffffffff8159cad8>] ? __schedule+0x648/0x870
[3326150.988015] WARN: [<ffffffff81088cf0>] ? rescuer_thread+0x300/0x300
[3326150.988023] WARN: [<ffffffff8108ddf5>] kthread+0xd5/0xe0
[3326150.988031] WARN: [<ffffffff8108dd20>] ? kthread_stop+0x110/0x110
[3326150.988040] WARN: [<ffffffff815a0bcf>] ret_from_fork+0x3f/0x70
[3326150.988048] WARN: [<ffffffff8108dd20>] ? kthread_stop+0x110/0x110
[3326150.988127] ALERT: RIP [<ffffffffa05ce70d>] iscsi_xmit_task+0x2d/0xc0 [libiscsi]
[3326150.988138] WARN: RSP <ffff8801f545bdb0>
[3326150.988144] WARN: CR2: 0000000000000078
[3326151.020366] WARN: ---[ end trace 1c60974d4678d81b ]---
Commit 6f8830f5bbab ("scsi: libiscsi: add lock around task lists to fix
list corruption regression") introduced "taskqueuelock" to fix list
corruption during the race, but this wasn't enough.
Re-setting of conn->task to NULL, could race with iscsi_xmit_task().
iscsi_complete_task()
{
....
if (conn->task == task)
conn->task = NULL;
}
conn->task in iscsi_xmit_task() could be NULL and so will be task.
__iscsi_get_task(task) will crash (NullPtr de-ref), trying to access
refcount.
iscsi_xmit_task()
{
struct iscsi_task *task = conn->task;
__iscsi_get_task(task);
}
This commit will take extra conn->session->back_lock in iscsi_xmit_task()
to ensure iscsi_xmit_task() waits for iscsi_complete_task(), if
iscsi_complete_task() wins the race. If iscsi_xmit_task() wins the race,
iscsi_xmit_task() increments task->refcount
(__iscsi_get_task) ensuring iscsi_complete_task() will not iscsi_free_task().
Signed-off-by: Anoob Soman <anoob.soman@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Acked-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
In qla2x00_async_tm_cmd, we reference off sp after it has been freed. This
caused a panic on a system running a slub debug kernel. Since fcport is
passed in anyways, just use that instead.
Signed-off-by: Bill Kuzeja <william.kuzeja@stratus.com>
Acked-by: Giridhar Malavali <gmalavali@marvell.com>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The problem is that the default for MQ is not to gather entropy, whereas
the default for the legacy queue was always to gather it. The original
attempt to fix entropy gathering for rotational disks under MQ added an
else branch in sd_read_block_characteristics(). Unfortunately, the entire
check isn't reached if the device has no characteristics VPD page. Since
this page was only introduced in SBC-3 and its optional anyway, most less
expensive rotational disks don't have one, meaning they all stopped
gathering entropy when we made MQ the default. In a wholly unrelated
change, openssl and openssh won't function until the random number
generator is initialised, meaning lots of people have been seeing large
delays before they could log into systems with default MQ kernels due to
this lack of entropy, because it now can take tens of minutes to initialise
the kernel random number generator.
The fix is to set the non-rotational and add-randomness flags
unconditionally early on in the disk initialization path, so they can be
reset only if the device actually reports being non-rotational via the VPD
page.
Reported-by: Mikael Pettersson <mikpelinux@gmail.com>
Fixes: 83e32a591077 ("scsi: sd: Contribute to randomness when running rotational device")
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Xuewei Zhang <xueweiz@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Presently when an error is encountered during probe of the cxlflash
adapter, a deadlock is seen with cpu thread stuck inside
cxlflash_remove(). Below is the trace of the deadlock as logged by
khungtaskd:
cxlflash 0006:00:00.0: cxlflash_probe: init_afu failed rc=-16
INFO: task kworker/80:1:890 blocked for more than 120 seconds.
Not tainted 5.0.0-rc4-capi2-kexec+ #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/80:1 D 0 890 2 0x00000808
Workqueue: events work_for_cpu_fn
Call Trace:
0x4d72136320 (unreliable)
__switch_to+0x2cc/0x460
__schedule+0x2bc/0xac0
schedule+0x40/0xb0
cxlflash_remove+0xec/0x640 [cxlflash]
cxlflash_probe+0x370/0x8f0 [cxlflash]
local_pci_probe+0x6c/0x140
work_for_cpu_fn+0x38/0x60
process_one_work+0x260/0x530
worker_thread+0x280/0x5d0
kthread+0x1a8/0x1b0
ret_from_kernel_thread+0x5c/0x80
INFO: task systemd-udevd:5160 blocked for more than 120 seconds.
The deadlock occurs as cxlflash_remove() is called from cxlflash_probe()
without setting 'cxlflash_cfg->state' to STATE_PROBED and the probe thread
starts to wait on 'cxlflash_cfg->reset_waitq'. Since the device was never
successfully probed the 'cxlflash_cfg->state' never changes from
STATE_PROBING hence the deadlock occurs.
We fix this deadlock by setting the variable 'cxlflash_cfg->state' to
STATE_PROBED in case an error occurs during cxlflash_probe() and just
before calling cxlflash_remove().
Cc: stable@vger.kernel.org
Fixes: c21e0bbfc485("cxlflash: Base support for IBM CXL Flash Adapter")
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This reverts commit bbc0f8bd88abefb0f27998f40a073634a3a2db89.
It added a warning whose intent was to check whether the rport was still
linked into the peer list. It doesn't work as intended and gives false
positive warnings for two reasons:
1) If the rport is never linked into the peer list it will not be
considered empty since the list_head is never initialized.
2) If the rport is deleted from the peer list using list_del_rcu(), then
the list_head is in an undefined state and it is not considered empty.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
README