linux-stable

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.

Branch: master

History

Linus Torvalds ad584d73a2 Tracing updates for 6.9: Main user visible change: - User events can now have "multi formats" The current user events have a single format. If another event is created with a different format, it will fail to be created. That is, once an event name is used, it cannot be used again with a different format. This can cause issues if a library is using an event and updates its format. An application using the older format will prevent an application using the new library from registering its event. A task could also DOS another application if it knows the event names, and it creates events with different formats. The multi-format event is in a different name space from the single format. Both the event name and its format are the unique identifier. This will allow two different applications to use the same user event name but with different payloads. - Added support to have ftrace_dump_on_oops dump out instances and not just the main top level tracing buffer. Other changes: - Add eventfs_root_inode Only the root inode has a dentry that is static (never goes away) and stores it upon creation. There's no reason that the thousands of other eventfs inodes should have a pointer that never gets set in its descriptor. Create a eventfs_root_inode desciptor that has a eventfs_inode descriptor and a dentry pointer, and only the root inode will use this. - Added WARN_ON()s in eventfs There's some conditionals remaining in eventfs that should never be hit, but instead of removing them, add WARN_ON() around them to make sure that they are never hit. - Have saved_cmdlines allocation also include the map_cmdline_to_pid array The saved_cmdlines structure allocates a large amount of data to hold its mappings. Within it, it has three arrays. Two are already apart of it: map_pid_to_cmdline[] and saved_cmdlines[]. More memory can be saved by also including the map_cmdline_to_pid[] array as well. - Restructure __string() and __assign_str() macros used in TRACE_EVENT(). Dynamic strings in TRACE_EVENT() are declared with: __string(name, source) And assigned with: __assign_str(name, source) In the tracepoint callback of the event, the __string() is used to get the size needed to allocate on the ring buffer and __assign_str() is used to copy the string into the ring buffer. There's a helper structure that is created in the TRACE_EVENT() macro logic that will hold the string length and its position in the ring buffer which is created by __string(). There are several trace events that have a function to create the string to save. This function is executed twice. Once for __string() and again for __assign_str(). There's no reason for this. The helper structure could also save the string it used in __string() and simply copy that into __assign_str() (it also already has its length). By using the structure to store the source string for the assignment, it means that the second argument to __assign_str() is no longer needed. It will be removed in the next merge window, but for now add a warning if the source string given to __string() is different than the source string given to __assign_str(), as the source to __assign_str() isn't even used and will be going away. - Added checks to make sure that the source of __string() is also the source of __assign_str() so that it can be safely removed in the next merge window. Included fixes that the above check found. - Other minor clean ups and fixes -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCZfhbUBQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qrhJAP9bfnYO7tfNGZVNPmTT7Fz0z4zCU1Pb P8M+24yiFTeFWwD/aIPlMFZONVkTdFAlLdffl6kJOKxZ7vW4XzUjfNWb6wo= =z/D6 -----END PGP SIGNATURE----- Merge tag 'trace-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: "Main user visible change: - User events can now have "multi formats" The current user events have a single format. If another event is created with a different format, it will fail to be created. That is, once an event name is used, it cannot be used again with a different format. This can cause issues if a library is using an event and updates its format. An application using the older format will prevent an application using the new library from registering its event. A task could also DOS another application if it knows the event names, and it creates events with different formats. The multi-format event is in a different name space from the single format. Both the event name and its format are the unique identifier. This will allow two different applications to use the same user event name but with different payloads. - Added support to have ftrace_dump_on_oops dump out instances and not just the main top level tracing buffer. Other changes: - Add eventfs_root_inode Only the root inode has a dentry that is static (never goes away) and stores it upon creation. There's no reason that the thousands of other eventfs inodes should have a pointer that never gets set in its descriptor. Create a eventfs_root_inode desciptor that has a eventfs_inode descriptor and a dentry pointer, and only the root inode will use this. - Added WARN_ON()s in eventfs There's some conditionals remaining in eventfs that should never be hit, but instead of removing them, add WARN_ON() around them to make sure that they are never hit. - Have saved_cmdlines allocation also include the map_cmdline_to_pid array The saved_cmdlines structure allocates a large amount of data to hold its mappings. Within it, it has three arrays. Two are already apart of it: map_pid_to_cmdline[] and saved_cmdlines[]. More memory can be saved by also including the map_cmdline_to_pid[] array as well. - Restructure __string() and __assign_str() macros used in TRACE_EVENT() Dynamic strings in TRACE_EVENT() are declared with: __string(name, source) And assigned with: __assign_str(name, source) In the tracepoint callback of the event, the __string() is used to get the size needed to allocate on the ring buffer and __assign_str() is used to copy the string into the ring buffer. There's a helper structure that is created in the TRACE_EVENT() macro logic that will hold the string length and its position in the ring buffer which is created by __string(). There are several trace events that have a function to create the string to save. This function is executed twice. Once for __string() and again for __assign_str(). There's no reason for this. The helper structure could also save the string it used in __string() and simply copy that into __assign_str() (it also already has its length). By using the structure to store the source string for the assignment, it means that the second argument to __assign_str() is no longer needed. It will be removed in the next merge window, but for now add a warning if the source string given to __string() is different than the source string given to __assign_str(), as the source to __assign_str() isn't even used and will be going away. - Added checks to make sure that the source of __string() is also the source of __assign_str() so that it can be safely removed in the next merge window. Included fixes that the above check found. - Other minor clean ups and fixes" * tag 'trace-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (34 commits) tracing: Add __string_src() helper to help compilers not to get confused tracing: Use strcmp() in __assign_str() WARN_ON() check tracepoints: Use WARN() and not WARN_ON() for warnings tracing: Use div64_u64() instead of do_div() tracing: Support to dump instance traces by ftrace_dump_on_oops tracing: Remove second parameter to __assign_rel_str() tracing: Add warning if string in __assign_str() does not match __string() tracing: Add __string_len() example tracing: Remove __assign_str_len() ftrace: Fix most kernel-doc warnings tracing: Decrement the snapshot if the snapshot trigger fails to register tracing: Fix snapshot counter going between two tracers that use it tracing: Use EVENT_NULL_STR macro instead of open coding "(null)" tracing: Use ? : shortcut in trace macros tracing: Do not calculate strlen() twice for __string() fields tracing: Rework __assign_str() and __string() to not duplicate getting the string cxl/trace: Properly initialize cxl_poison region name net: hns3: tracing: fix hclgevf trace event strings drm/i915: Add missing ; to __assign_str() macros in tracepoint code NFSD: Fix nfsd_clid_class use of __string_len() macro ...		2 months ago
..
acrn	virt: acrn: Replace obsolete memalign() with posix_memalign()	1 year ago
auxdisplay	.gitignore: prefix local generated files with a slash	3 years ago
binderfs	.gitignore: prefix local generated files with a slash	3 years ago
bpf	bpf-next-for-netdev	2 months ago
cgroup	samples/cgroup: add .gitignore file for generated samples	3 months ago
configfs	treewide: remove editor modelines and cruft	3 years ago
connector	.gitignore: prefix local generated files with a slash	3 years ago
coresight	coresight: syscfg: Example CoreSight configuration loadable module	2 years ago
fanotify	Add gitignore file for samples/fanotify/ subdirectory	3 years ago
fprobe	fprobe: Pass return address to the handlers	11 months ago
ftrace	RISC-V Patches for the 6.8 Merge Window, Part 4	3 months ago
hid	bpf: Replace deprecated -target with --target= for Clang	10 months ago
hidraw	.gitignore: prefix local generated files with a slash	3 years ago
hw_breakpoint	samples/hw_breakpoint: mark sample_hbp as static	9 months ago
kdb	kdb: Rename members of struct kdbtab_t	3 years ago
kfifo	samples/kfifo: Rename read_lock/write_lock	3 years ago
kmemleak	kmemleak-test: drop __init to get better backtrace	11 months ago
kobject	samples/kobject: make kobj_type structure constant	1 year ago
kprobes	samples: kprobes: Fixes a typo	7 months ago
landlock	samples/landlock: Don't error out if a file path cannot be opened	2 months ago
livepatch	livepatch: Reorder to use before freeing a pointer	2 years ago
mei	samples: mei: don't wait on read completion upon write.	3 years ago
nitro_enclaves	nitro_enclaves: Add fixes for checkpatch blank line reports	3 years ago
pfsm	samples: Add userspace example for TI TPS6594 PFSM	11 months ago
pidfd	.gitignore: prefix local generated files with a slash	3 years ago
pktgen	samples: pktgen: fix append mode failed issue	10 months ago
qmi	soc: qcom: qmi: use const for struct qmi_elem_info	2 years ago
rpmsg	…
rust	samples: rust: print: Add sample code for Arc printing	1 year ago
seccomp	samples: user-trap: fix strict-aliasing warning	3 months ago
timers	.gitignore: prefix local generated files with a slash	3 years ago
trace_events	tracing: Remove second parameter to __assign_rel_str()	2 months ago
trace_printk	…
uhid	kbuild: introduce hostprogs-always-y and userprogs-always-y	4 years ago
user_events	tracing/user_events: Use write ABI in example	1 year ago
v4l	media updates for v6.8-rc1	4 months ago
vfio-mdev	vfio/mbochs: make mbochs_class constant	2 months ago
vfs	.gitignore: prefix local generated files with a slash	3 years ago
watch_queue	.gitignore: prefix local generated files with a slash	3 years ago
watchdog	.gitignore: prefix local generated files with a slash	3 years ago
Kconfig	samples: introduce new samples subdir for cgroup	5 months ago
Makefile	samples: introduce new samples subdir for cgroup	5 months ago