linux/tools
Namhyung Kim 295d8a03ca perf tools: Fallback to initial kernel map properly
In maps__split_kallsyms(), it assumes new kernel map when it finds a
symbol without module after any module and the initial kernel map has
some symbols.  Because it expects modules are out of the kernel map so
modules should not have symbols in the kernel map.

For example, the following memory map shows symbols and maps.  Any
symbols in the module 1 area will go to the module 1.  The main kernel
map starts at 0xffffffffbc200000.  But if any symbol has a module
between the symbols in that area, next symbols after 0xffffffffbd008000
will generate new kernel maps like [kernel].1.

   kernel address   |                     |
                    |                     |
 0xffffffffc0000000 |---------------------|
                    |     (symbols)       |
                    |        ...          |   <---  [kernel].N
 0xffffffffbc400000 |---------------------|
                    |     (symbols)       |
                    |      module 2       |   <---  bad?
 0xffffffffbc380000 |---------------------|
                    |        ...          |
                    |     (symbols)       |
                    |  [kernel.kallsyms]  |   <---  initial map
 0xffffffffbc200000 |---------------------|
                    |                     |
                    |                     |
 0xffffffffabcde000 |---------------------|
                    |     (symbols)       |
                    |      module 1       |
 0xffffffffabcd0000 |---------------------|

This is very fragile when the module has a symbol that falls into the
main kernel map for some reason.  My system has a livepatch module with
such symbols.  And it created a lot of new kernel maps after those
symbols.  But the symbol may have broken addresses and the later symbols
can still be found in the initial kernel map.

Let's check the symbol address in the initial map and use it if found.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2025-12-02 21:59:14 -08:00
..
accounting tools/delaytop: improve error handling for missing PSI support 2025-09-13 17:32:56 -07:00
arch tools: arm64: Add Cortex-A720AE definitions 2025-10-23 14:48:15 -07:00
bootconfig
bpf bpftool: Remove duplicate string.h header 2025-09-27 04:23:15 -07:00
build tool build: Remove __get_cpuid feature test 2025-11-13 23:03:11 -08:00
certs
cgroup
counter
crypto
debugging
docs docs: add tools/docs/gen-redirects.py 2025-09-09 13:37:16 -06:00
firewire
firmware
gpio tools: gpio: remove the include directory on make clean 2025-09-04 16:29:28 +02:00
hv
iio iio: add power and energy measurement modifiers 2025-09-13 13:47:19 +01:00
include tools headers UAPI: Sync linux/perf_event.h for deferred callchains 2025-12-02 16:13:32 -08:00
kvm/kvm_stat
laptop
leds
lib perf tools: Minimal DEFERRED_CALLCHAIN support 2025-12-02 16:13:32 -08:00
memory-model
mm tools/mm/slabinfo: fix access to null terminator in string boundary 2025-09-21 14:22:00 -07:00
net NFSD 6.18 Release Notes 2025-10-06 13:22:21 -07:00
objtool - Remove a bunch of asm implementing condition flags testing in KVM's 2025-10-11 11:19:16 -07:00
pcmcia
perf perf tools: Fallback to initial kernel map properly 2025-12-02 21:59:14 -08:00
power Kbuild updates for 6.18 2025-10-01 20:58:51 -07:00
rcu
sched
sched_ext tools/sched_ext: scx_qmap: Make debug output quieter by default 2025-09-23 09:03:26 -10:00
scripts
sound
spi
testing bpf-fixes 2025-10-11 10:31:38 -07:00
thermal
time
tracing rtla: Updates for v6.18 2025-10-05 09:38:26 -07:00
usb tools/usb/usbip: fix spelling mistakes in usbipd.c 2025-09-06 15:22:14 +02:00
verification
virtio kmsan: convert kmsan_handle_dma to use physical addresses 2025-09-12 00:18:20 +02:00
wmi
workqueue
writeback
Makefile