linux.git/kernel/trace/blktrace.c, branch v6.18.21

Merge tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-08-03T23:23:09+00:00

Pull non-MM updates from Andrew Morton:
 "Significant patch series in this pull request:

   - "squashfs: Remove page->mapping references" (Matthew Wilcox) gets
     us closer to being able to remove page->mapping

   - "relayfs: misc changes" (Jason Xing) does some maintenance and
     minor feature addition work in relayfs

   - "kdump: crashkernel reservation from CMA" (Jiri Bohac) switches
     us from static preallocation of the kdump crashkernel's working
     memory over to dynamic allocation. So the difficulty of a-priori
     estimation of the second kernel's needs is removed and the first
     kernel obtains extra memory

   - "generalize panic_print's dump function to be used by other
     kernel parts" (Feng Tang) implements some consolidation and
     rationalization of the various ways in which a failing kernel
     splats information at the operator

* tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (80 commits)
  tools/getdelays: add backward compatibility for taskstats version
  kho: add test for kexec handover
  delaytop: enhance error logging and add PSI feature description
  samples: Kconfig: fix spelling mistake "instancess" -> "instances"
  fat: fix too many log in fat_chain_add()
  scripts/spelling.txt: add notifer||notifier to spelling.txt
  xen/xenbus: fix typo "notifer"
  net: mvneta: fix typo "notifer"
  drm/xe: fix typo "notifer"
  cxl: mce: fix typo "notifer"
  KVM: x86: fix typo "notifer"
  MAINTAINERS: add maintainers for delaytop
  ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below()
  ucount: fix atomic_long_inc_below() argument type
  kexec: enable CMA based contiguous allocation
  stackdepot: make max number of pools boot-time configurable
  lib/xxhash: remove unused functions
  init/Kconfig: restore CONFIG_BROKEN help text
  lib/raid6: update recov_rvv.c zero page usage
  docs: update docs after introducing delaytop
  ...

blktrace: add zoned block commands to blk_fill_rwbs

2025-07-15T14:03:48+00:00

Add zoned block commands to blk_fill_rwbs:

- ZONE APPEND will be decoded as 'ZA'
- ZONE RESET will be decoded as 'ZR'
- ZONE RESET ALL will be decoded as 'ZRA'
- ZONE FINISH will be decoded as 'ZF'
- ZONE OPEN will be decoded as 'ZO'
- ZONE CLOSE will be decoded as 'ZC'

Reviewed-by: Chaitanya Kulkarni 
Signed-off-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20250715115324.53308-2-johannes.thumshirn@wdc.com
Signed-off-by: Jens Axboe

blktrace: use rbuf->stats.full as a drop indicator in relayfs

2025-07-10T05:57:52+00:00

Replace internal subbuf_start in blktrace with the default policy in
relayfs.

Remove dropped field from struct blktrace.  Correspondingly, call the
common helper in relay.  By incrementing full_count to keep track of how
many times we encountered a full buffer issue, user space will know how
many events were lost.

Link: https://lkml.kernel.org/r/20250612061201.34272-5-kerneljasonxing@gmail.com
Signed-off-by: Jason Xing 
Reviewed-by: Yushan Zhou 
Reviewed-by: Jens Axboe 
Reviewed-by: Masami Hiramatsu (Google) 
Cc: Mathieu Desnoyers 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton

relayfs: abolish prev_padding

2025-07-10T05:57:51+00:00

Patch series "relayfs: misc changes", v5.

The series mostly focuses on the error counters which helps every user
debug their own kernel module.


This patch (of 5):

prev_padding represents the unused space of certain subbuffer.  If the
content of a call of relay_write() exceeds the limit of the remainder of
this subbuffer, it will skip storing in the rest space and record the
start point as buf->prev_padding in relay_switch_subbuf().  Since the buf
is a per-cpu big buffer, the point of prev_padding as a global value for
the whole buffer instead of a single subbuffer (whose padding info is
stored in buf->padding[]) seems meaningless from the real use cases, so we
don't bother to record it any more.

Link: https://lkml.kernel.org/r/20250612061201.34272-1-kerneljasonxing@gmail.com
Link: https://lkml.kernel.org/r/20250612061201.34272-2-kerneljasonxing@gmail.com
Signed-off-by: Jason Xing 
Reviewed-by: Yushan Zhou 
Reviewed-by: Masami Hiramatsu (Google) 
Cc: Jens Axboe 
Cc: Mathieu Desnoyers 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton

traceevent/block: Add REQ_ATOMIC flag to block trace events

2025-05-23T15:18:48+00:00

Filesystems like XFS can implement atomic write I/O using either
REQ_ATOMIC flag set in the bio or via CoW operation. It will be useful
if we have a flag in trace events to distinguish between the two. This
patch adds char 'U' (Untorn writes) to rwbs field of the trace events
if REQ_ATOMIC flag is set in the bio.


=================
xfs_io-4238    [009] .....  4148.126843: block_rq_issue: 259,0 WFSU 16384 () 768 + 32 none,0,0 [xfs_io]
-0       [009] d.h1.  4148.129864: block_rq_complete: 259,0 WFSU () 768 + 32 none,0,0 [0]


===============
xfs_io-4237    [010] .....  4143.325616: block_rq_issue: 259,0 WS 16384 () 768 + 32 none,0,0 [xfs_io]
-0       [010] d.H1.  4143.329138: block_rq_complete: 259,0 WS () 768 + 32 none,0,0 [0]

Signed-off-by: Ritesh Harjani (IBM) 
Reviewed-by: Ojaswin Mujoo 
Link: https://lore.kernel.org/r/44317cb2ec4588f6a2c1501a96684e6a1196e8ba.1747921498.git.ritesh.list@gmail.com
Signed-off-by: Jens Axboe

block: remove bounce buffering support

2025-05-05T19:22:39+00:00

The block layer bounce buffering support is unused now, remove it.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Reviewed-by: John Garry 
Reviewed-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20250505081138.3435992-7-hch@lst.de
Signed-off-by: Jens Axboe

blktrace: remove redundant return at end of function

2024-12-23T15:17:23+00:00

A recent change added return 0 before an existing return statement
at the end of function blk_trace_setup. The final return is now
redundant, so remove it.

Fixes: 64d124798244 ("blktrace: move copy_[to|from]_user() out of ->debugfs_lock")
Signed-off-by: Colin Ian King 
Link: https://lore.kernel.org/r/20241204150450.399005-1-colin.i.king@gmail.com
Signed-off-by: Jens Axboe

blktrace: move copy_[to|from]_user() out of ->debugfs_lock

2024-12-23T15:17:22+00:00

Move copy_[to|from]_user() out of ->debugfs_lock and cut the dependency
between mm->mmap_lock and q->debugfs_lock, then we avoids lots of
lockdep false positive warning. Obviously ->debug_lock isn't needed
for copy_[to|from]_user().

The only behavior change is to call blk_trace_remove() in case of setup
failure handling by re-grabbing ->debugfs_lock, and this way is just
fine since we do cover concurrent setup() & remove().

Reported-by: syzbot+91585b36b538053343e4@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-block/67450fd4.050a0220.1286eb.0007.GAE@google.com/
Closes: https://lore.kernel.org/linux-block/6742e584.050a0220.1cc393.0038.GAE@google.com/
Closes: https://lore.kernel.org/linux-block/6742a600.050a0220.1cc393.002e.GAE@google.com/
Closes: https://lore.kernel.org/linux-block/67420102.050a0220.1cc393.0019.GAE@google.com/
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20241128125029.4152292-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe

blktrace: don't centralize grabbing q->debugfs_mutex in blk_trace_ioctl

2024-12-23T15:17:22+00:00

Call each handler directly and the handler do grab q->debugfs_mutex,
prepare for killing dependency between ->debug_mutex and ->mmap_lock.

Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20241128125029.4152292-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe

blktrace: convert strncpy() to strscpy_pad()

2024-04-26T04:07:08+00:00

gcc-9 warns about a possibly non-terminated string copy:

kernel/trace/blktrace.c: In function 'do_blk_trace_setup':
kernel/trace/blktrace.c:527:2: error: 'strncpy' specified bound 32 equals destination size [-Werror=stringop-truncation]

Newer versions are fine here because they see the following explicit
nul-termination. Using strscpy_pad() avoids the warning and
simplifies the code a little. The padding helps  give a clean
buffer to userspace.

Link: https://lkml.kernel.org/r/20240409140059.3806717-5-arnd@kernel.org
Signed-off-by: Arnd Bergmann 
Acked-by: Justin Stitt 
Cc: Alexey Starikovskiy 
Cc: Bob Moore 
Cc: Jens Axboe 
Cc: Len Brown 
Cc: Lin Ming 
Cc: Masahiro Yamada 
Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: Nathan Chancellor 
Cc: Nicolas Schier 
Cc: Rafael J. Wysocki 
Cc: "Richard Russon (FlatCap)" 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton