Vasily Gorbik cd57953936 s390/kprobes: fix current_kprobe never cleared after kprobes reenter ... Recent test_kprobe_missed kprobes kunit test uncovers the following problem. Once kprobe is triggered from another kprobe (kprobe reenter), all future kprobes on this cpu are considered as kprobe reenter, thus pre_handler and post_handler are not being called and kprobes are counted as "missed". Commit b9599798f9 ("[S390] kprobes: activation and deactivation") introduced a simpler scheme for kprobes (de)activation and status tracking by using push_kprobe/pop_kprobe, which supposed to work for both initial kprobe entry as well as kprobe reentry and helps to avoid handling those two cases differently. The problem is that a sequence of calls in case of kprobes reenter: push_kprobe() <- NULL (current_kprobe) push_kprobe() <- kprobe1 (current_kprobe) pop_kprobe() -> kprobe1 (current_kprobe) pop_kprobe() -> kprobe1 (current_kprobe) leaves "kprobe1" as "current_kprobe" on this cpu, instead of setting it to NULL. In fact push_kprobe/pop_kprobe can only store a single state (there is just one prev_kprobe in kprobe_ctlblk). Which is a hack but sufficient, there is no need to have another prev_kprobe just to store NULL. To make a simple and backportable fix simply reset "prev_kprobe" when kprobe is poped from this "stack". No need to worry about "kprobe_status" in this case, because its value is only checked when current_kprobe != NULL. Cc: stable@vger.kernel.org Fixes: b9599798f9 ("[S390] kprobes: activation and deactivation") Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>		2023-03-02 15:33:11 +01:00
..
appldata	s390/appldata: remove power management callbacks	2022-12-02 18:25:04 +01:00
boot	s390/decompressor: add link map saving	2023-02-28 13:19:06 +01:00
configs	s390: update defconfigs	2023-01-11 21:26:40 +01:00
crypto	This update includes the following changes:	2023-02-21 18:10:50 -08:00
hypfs	s390/hypfs: remove unused info_blk_hdr__pcpus() function	2022-11-23 16:24:07 +01:00
include	s390/mcck: cleanup user process termination path	2023-02-28 13:19:05 +01:00
kernel	s390/kprobes: fix current_kprobe never cleared after kprobes reenter	2023-03-02 15:33:11 +01:00
kvm	KVM: s390: interrupt: use READ_ONCE() before cmpxchg()	2023-01-11 15:28:47 +01:00
lib	s390/kprobes: replace kretprobe with rethook	2023-01-22 18:42:35 +01:00
mm	s390/extmem: return correct segment type in __segment_load()	2023-03-01 20:01:34 +01:00
net	s390/bpf: Implement bpf_jit_supports_kfunc_call()	2023-01-29 19:16:29 -08:00
pci	IOMMU Updates for Linux v6.2	2022-12-19 08:34:39 -06:00
purgatory	s390/purgatory: remove duplicated build rule of kexec-purgatory.o	2022-06-30 14:18:16 +02:00
tools	KVM: s390: Add facility 197 to the allow list	2022-07-13 15:25:25 +02:00
Kbuild
Kconfig	s390/Kconfig: sort config S390 select list again	2023-03-01 20:01:34 +01:00
Kconfig.debug	s390/Kconfig.debug: fix indentation	2022-06-01 12:03:15 +02:00
Makefile	s390: always build relocatable kernel	2022-11-08 19:32:32 +01:00