Re: [PATCH RFCv2 06/18] uprobes: Add orig argument to uprobe_write and uprobe_write_opcode
From: Andrii Nakryiko <hidden>
Date: 2025-02-28 19:07:52
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bpf, lkml
On Mon, Feb 24, 2025 at 6:03 AM Jiri Olsa [off-list ref] wrote:
The uprobe_write has special path to restore the original page when we write original instruction back. This happens when uprobe_write detects that we want to write anything else but breakpoint instruction. In following changes we want to use uprobe_write function for multiple updates, so adding new function argument to denote that this is the original instruction update. This way uprobe_write can make appropriate checks and restore the original page when possible. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- arch/arm/probes/uprobes/core.c | 2 +- include/linux/uprobes.h | 5 +++-- kernel/events/uprobes.c | 22 ++++++++++------------ 3 files changed, 14 insertions(+), 15 deletions(-)
[...]
quoted hunk ↗ jump to hunk
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index ad5879fc2d26..2b542043089e 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c@@ -471,25 +471,23 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm, * Return 0 (success) or a negative errno. */ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, - unsigned long vaddr, uprobe_opcode_t opcode) + unsigned long vaddr, uprobe_opcode_t opcode, bool orig) { - return uprobe_write(auprobe, mm, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE, verify_opcode); + return uprobe_write(auprobe, mm, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE, verify_opcode, orig); } int uprobe_write(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *insn, - int nbytes, uprobe_write_verify_t verify) + int nbytes, uprobe_write_verify_t verify, bool orig)
why not call orig -> is_register and avoid a bunch of code churn?... (and while "is_register" is not awesome name, still a bit more clear compared to "orig", IMO)
{
struct page *old_page, *new_page;
struct vm_area_struct *vma;
- int ret, is_register;
+ int ret;
bool orig_page_huge = false;
unsigned int gup_flags = FOLL_FORCE;
- is_register = is_swbp_insn(insn);
-[...]