Stephen Brennan 1a7d0890dd kprobe/ftrace: bail out if ftrace was killed ... If an error happens in ftrace, ftrace_kill() will prevent disarming kprobes. Eventually, the ftrace_ops associated with the kprobes will be freed, yet the kprobes will still be active, and when triggered, they will use the freed memory, likely resulting in a page fault and panic. This behavior can be reproduced quite easily, by creating a kprobe and then triggering a ftrace_kill(). For simplicity, we can simulate an ftrace error with a kernel module like [1]: [1]: https://github.com/brenns10/kernel_stuff/tree/master/ftrace_killer sudo perf probe --add commit_creds sudo perf trace -e probe:commit_creds # In another terminal make sudo insmod ftrace_killer.ko # calls ftrace_kill(), simulating bug # Back to perf terminal # ctrl-c sudo perf probe --del commit_creds After a short period, a page fault and panic would occur as the kprobe continues to execute and uses the freed ftrace_ops. While ftrace_kill() is supposed to be used only in extreme circumstances, it is invoked in FTRACE_WARN_ON() and so there are many places where an unexpected bug could be triggered, yet the system may continue operating, possibly without the administrator noticing. If ftrace_kill() does not panic the system, then we should do everything we can to continue operating, rather than leave a ticking time bomb. Link: https://lore.kernel.org/all/20240501162956.229427-1-stephen.s.brennan@oracle.com/ Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Guo Ren <guoren@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>		2024-05-16 07:23:30 +09:00
..
boot	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
configs	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
crypto	crypto: riscv - add vector crypto accelerated AES-CBC-CTS	2024-03-20 08:56:11 -07:00
errata	Merge patch series "RISC-V: Test th.sxstatus.MAEE bit before enabling MAEE"	2024-04-26 10:21:57 -07:00
include	Merge patch series "RISC-V: Test th.sxstatus.MAEE bit before enabling MAEE"	2024-04-26 10:21:57 -07:00
kernel	kprobe/ftrace: bail out if ftrace was killed	2024-05-16 07:23:30 +09:00
kvm	RISC-V: KVM: Fix APLIC in_clrip[x] read emulation	2024-03-26 09:40:55 +05:30
lib	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
mm	Merge patch the fixes from "riscv: 64-bit NOMMU fixes and enhancements"	2024-04-09 11:41:01 -07:00
net	riscv, bpf: Fix kfunc parameters incompatibility between bpf and riscv abi	2024-03-25 11:39:31 -07:00
purgatory	riscv: Use SYM_*() assembly macros instead of deprecated ones	2023-11-06 09:42:47 -08:00
tools	riscv: Check relocations at compile time	2023-04-19 07:46:32 -07:00
Kbuild	RISC-V: hook new crypto subdir into build-system	2024-01-22 17:55:17 -08:00
Kconfig	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
Kconfig.debug	riscv: Add tests for riscv module loading	2023-11-07 14:59:32 -08:00
Kconfig.errata	riscv: thead: Rename T-Head PBMT to MAE	2024-04-25 10:22:33 -07:00
Kconfig.socs	riscv: dts: Move BUILTIN_DTB_SOURCE to common Kconfig	2024-03-06 00:08:32 +00:00
Makefile	riscv: compat_vdso: install compat_vdso.so.dbg to /lib/modules/*/vdso/	2024-03-26 14:08:02 -07:00
Makefile.postlink	kbuild: remove ARCH_POSTLINK from module builds	2023-10-28 21:10:08 +09:00