Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 219 insertions, 0 deletions

diff --git a/scripts/Makefile.warn b/scripts/Makefile.warn
new file mode 100644
index 000000000..35af7d6c6
--- /dev/null
+++ b/scripts/Makefile.warn
@@ -0,0 +1,219 @@
+# SPDX-License-Identifier: GPL-2.0
+# ==========================================================================
+# make W=... settings
+#
+# There are four warning groups enabled by W=1, W=2, W=3, and W=e
+# They are independent, and can be combined like W=12 or W=123e.
+# ==========================================================================
+
+# Default set of warnings, always enabled
+KBUILD_CFLAGS += -Wall
+KBUILD_CFLAGS += -Wextra
+KBUILD_CFLAGS += -Wundef
+KBUILD_CFLAGS += -Werror=implicit-function-declaration
+KBUILD_CFLAGS += -Werror=implicit-int
+KBUILD_CFLAGS += -Werror=return-type
+KBUILD_CFLAGS += -Werror=strict-prototypes
+KBUILD_CFLAGS += -Wno-format-security
+KBUILD_CFLAGS += -Wno-trigraphs
+KBUILD_CFLAGS += -Wno-frame-address
+KBUILD_CFLAGS += $(call cc-option, -Wno-address-of-packed-member)
+KBUILD_CFLAGS += -Wmissing-declarations
+KBUILD_CFLAGS += -Wmissing-prototypes
+
+ifneq ($(CONFIG_FRAME_WARN),0)
+KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_FRAME_WARN)
+endif
+
+KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
+
+ifdef CONFIG_CC_IS_CLANG
+# Clang checks for overflow/truncation with '%p', while GCC does not:
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219
+KBUILD_CFLAGS += $(call cc-option, -Wno-format-overflow-non-kprintf)
+KBUILD_CFLAGS += $(call cc-option, -Wno-format-truncation-non-kprintf)
+
+# Clang may emit a warning when a const variable, such as the dummy variables
+# in typecheck(), or const member of an aggregate type are not initialized,
+# which can result in unexpected behavior. However, in many audited cases of
+# the "field" variant of the warning, this is intentional because the field is
+# never used within a particular call path, the field is within a union with
+# other non-const members, or the containing object is not const so the field
+# can be modified via memcpy() / memset(). While the variable warning also gets
+# disabled with this same switch, there should not be too much coverage lost
+# because -Wuninitialized will still flag when an uninitialized const variable
+# is used.
+KBUILD_CFLAGS += $(call cc-option, -Wno-default-const-init-unsafe)
+else
+
+# gcc inanely warns about local variables called 'main'
+KBUILD_CFLAGS += -Wno-main
+endif
+
+# Too noisy on range checks and in macros handling both signed and unsigned.
+KBUILD_CFLAGS += -Wno-type-limits
+
+# These result in bogus false positives
+KBUILD_CFLAGS += $(call cc-option, -Wno-dangling-pointer)
+
+# Stack Variable Length Arrays (VLAs) must not be used in the kernel.
+# Function array parameters should, however, be usable, but -Wvla will
+# warn for those. Clang has no way yet to distinguish between the VLA
+# types, so depend on GCC for now to keep stack VLAs out of the tree.
+# https://github.com/llvm/llvm-project/issues/57098
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98217
+KBUILD_CFLAGS += $(call cc-option,-Wvla-larger-than=1)
+
+# disable pointer signed / unsigned warnings in gcc 4.0
+KBUILD_CFLAGS += -Wno-pointer-sign
+
+# In order to make sure new function cast mismatches are not introduced
+# in the kernel (to avoid tripping CFI checking), the kernel should be
+# globally built with -Wcast-function-type.
+KBUILD_CFLAGS += -Wcast-function-type
+
+# Currently, disable -Wstringop-overflow for GCC 11, globally.
+KBUILD_CFLAGS-$(CONFIG_CC_NO_STRINGOP_OVERFLOW) += $(call cc-option, -Wno-stringop-overflow)
+KBUILD_CFLAGS-$(CONFIG_CC_STRINGOP_OVERFLOW) += $(call cc-option, -Wstringop-overflow)
+
+# Currently, disable -Wunterminated-string-initialization as broken
+KBUILD_CFLAGS += $(call cc-option, -Wno-unterminated-string-initialization)
+
+# The allocators already balk at large sizes, so silence the compiler
+# warnings for bounds checks involving those possible values. While
+# -Wno-alloc-size-larger-than would normally be used here, earlier versions
+# of gcc (<9.1) weirdly don't handle the option correctly when _other_
+# warnings are produced (?!). Using -Walloc-size-larger-than=SIZE_MAX
+# doesn't work (as it is documented to), silently resolving to "0" prior to
+# version 9.1 (and producing an error more recently). Numeric values larger
+# than PTRDIFF_MAX also don't work prior to version 9.1, which are silently
+# ignored, continuing to default to PTRDIFF_MAX. So, left with no other
+# choice, we must perform a versioned check to disable this warning.
+# https://lore.kernel.org/lkml/20210824115859.187f272f@canb.auug.org.au
+KBUILD_CFLAGS-$(call gcc-min-version, 90100) += -Wno-alloc-size-larger-than
+KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
+
+# Prohibit date/time macros, which would make the build non-deterministic
+KBUILD_CFLAGS += -Werror=date-time
+
+# enforce correct pointer usage
+KBUILD_CFLAGS += -Werror=incompatible-pointer-types
+
+# Require designated initializers for all marked structures
+KBUILD_CFLAGS += $(call cc-option,-Werror=designated-init)
+
+# Warn if there is an enum types mismatch
+KBUILD_CFLAGS += $(call cc-option,-Wenum-conversion)
+
+KBUILD_CFLAGS += -Wunused
+
+#
+# W=1 - warnings which may be relevant and do not occur too often
+#
+ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
+
+KBUILD_CFLAGS += -Wmissing-format-attribute
+KBUILD_CFLAGS += -Wmissing-include-dirs
+KBUILD_CFLAGS += -Wunused-const-variable
+
+KBUILD_CPPFLAGS += -Wundef
+KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1
+
+else
+
+# Some diagnostics enabled by default are noisy.
+# Suppress them by using -Wno... except for W=1.
+KBUILD_CFLAGS += -Wno-unused-but-set-variable
+KBUILD_CFLAGS += -Wno-unused-const-variable
+KBUILD_CFLAGS += $(call cc-option, -Wno-packed-not-aligned)
+KBUILD_CFLAGS += $(call cc-option, -Wno-format-overflow)
+ifdef CONFIG_CC_IS_GCC
+KBUILD_CFLAGS += -Wno-format-truncation
+endif
+KBUILD_CFLAGS += $(call cc-option, -Wno-stringop-truncation)
+
+KBUILD_CFLAGS += -Wno-override-init # alias for -Wno-initializer-overrides in clang
+
+ifdef CONFIG_CC_IS_CLANG
+KBUILD_CFLAGS += -Wno-pointer-to-enum-cast
+KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare
+KBUILD_CFLAGS += -Wno-unaligned-access
+KBUILD_CFLAGS += -Wno-enum-compare-conditional
+endif
+
+endif
+
+#
+# W=2 - warnings which occur quite often but may still be relevant
+#
+ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
+
+KBUILD_CFLAGS += -Wdisabled-optimization
+KBUILD_CFLAGS += -Wshadow
+KBUILD_CFLAGS += $(call cc-option, -Wlogical-op)
+KBUILD_CFLAGS += -Wunused-macros
+
+KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2
+
+else
+
+# The following turn off the warnings enabled by -Wextra
+KBUILD_CFLAGS += -Wno-missing-field-initializers
+KBUILD_CFLAGS += -Wno-shift-negative-value
+
+ifdef CONFIG_CC_IS_CLANG
+KBUILD_CFLAGS += -Wno-enum-enum-conversion
+endif
+
+ifdef CONFIG_CC_IS_GCC
+KBUILD_CFLAGS += -Wno-maybe-uninitialized
+endif
+
+endif
+
+#
+# W=3 - more obscure warnings, can most likely be ignored
+#
+ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
+
+KBUILD_CFLAGS += -Wbad-function-cast
+KBUILD_CFLAGS += -Wcast-align
+KBUILD_CFLAGS += -Wcast-qual
+KBUILD_CFLAGS += -Wconversion
+KBUILD_CFLAGS += -Wpacked
+KBUILD_CFLAGS += -Wpadded
+KBUILD_CFLAGS += -Wpointer-arith
+KBUILD_CFLAGS += -Wredundant-decls
+KBUILD_CFLAGS += -Wsign-compare
+KBUILD_CFLAGS += -Wswitch-default
+
+KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3
+
+else
+
+# The following turn off the warnings enabled by -Wextra
+KBUILD_CFLAGS += -Wno-sign-compare
+KBUILD_CFLAGS += -Wno-unused-parameter
+
+endif
+
+#
+# W=e and CONFIG_WERROR - error out on warnings
+#
+ifneq ($(findstring e, $(KBUILD_EXTRA_WARN))$(CONFIG_WERROR),)
+
+KBUILD_CPPFLAGS		+= -Werror
+KBUILD_AFLAGS		+= -Wa,--fatal-warnings
+KBUILD_LDFLAGS		+= --fatal-warnings
+KBUILD_USERCFLAGS	+= -Werror
+KBUILD_USERLDFLAGS	+= -Wl,--fatal-warnings
+KBUILD_RUSTFLAGS	+= -Dwarnings
+
+# While hostprog flags are used during build bootstrapping (thus should not
+# depend on CONFIG_ symbols), -Werror is disruptive and should be opted into.
+# Only apply -Werror to hostprogs built after the initial Kconfig stage.
+KBUILD_HOSTCFLAGS	+= -Werror
+KBUILD_HOSTLDFLAGS	+= -Wl,--fatal-warnings
+KBUILD_HOSTRUSTFLAGS	+= -Dwarnings
+
+endif