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CVE-2026-98888

arm64: kprobes: Allow reentering kprobes while single-stepping PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: arm64: kprobes: Allow reentering kprobes while single-stepping A kprobe can be hit while another kprobe is in KPROBE_HIT_SS state. This can happen when tracing or perf code runs from the debug exception path while the first kprobe is preparing or executing its out-of-line single-step instruction. Currently arm64 treats a kprobe hit in KPROBE_HIT_SS as unrecoverable, the same as a hit in KPROBE_REENTER. This is too strict. A hit in KPROBE_HIT_SS is still a one-level reentry and can be handled by saving the current kprobe state and setting up single-step for the new probe, just like reentry from KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE. The truly unrecoverable case is hitting another kprobe while already in KPROBE_REENTER, because the reentry save area has already been consumed. Move KPROBE_HIT_SS to the recoverable reentry cases and leave KPROBE_REENTER as the unrecoverable nested reentry case. This change also requires saving saved_irqflag in struct prev_kprobe. When a nested kprobe calls kprobes_save_local_irqflag(), it overwrites kcb->saved_irqflag with the currently masked DAIF value, losing the outer kprobe's original DAIF state. Without this fix, when the outer kprobe's single-step finishes, kprobes_restore_local_irqflag() applies the wrong DAIF mask and leaves interrupts permanently disabled. Extend struct prev_kprobe with a saved_irqflag field and save/restore it alongside kp and status. This ensures the outer kprobe's original interrupt state is preserved across reentry. This mirrors the x86 fix in commit 6a5022a56ac3 ("kprobes/x86: Allow to handle reentered kprobe on single-stepping").

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before bb0fe9121aa0824211aafa33c7d0151fd25ddb75; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before f96a0606de6bcc8d937b80e6470fd7a174c17e26; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 1f342b3e44c3035a837b53b217d816f7511c0d0a; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before c8e84e292ed4cfc199824146da71bb4397b02a1f; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 68774caca799e9695db56d426c69acebd041c2ed; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before a21bf9cb893126e8d9730995708d0be5eb167652; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 23f851ac0078a908bf3422d6467ebc1db5828c46; affected 0 before 5.10.271; affected 0 before 5.15.222; affected 0 before 6.1.189; affected 0 before 6.6.158; affected 0 before 6.12.111; affected 0 before 6.18.53
Linux / Linuxunaffected 5.10.271 through 5.10.*; unaffected 5.15.222 through 5.15.*; unaffected 6.1.189 through 6.1.*; unaffected 6.6.158 through 6.6.*; unaffected 6.12.111 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References