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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-06-14 18:44:00 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-08-24 09:19:21 +0300 |
| commit | 2dea1d9c38e481051fa0e62807e518c5768e62dd (patch) | |
| tree | 877c2d6807f79bc12d1a2deab136ed4d7466df68 /arch | |
| parent | ec4189c4e8eea0c5e7c9b71cb1502cdcbb32aa17 (diff) | |
| download | linux-2dea1d9c38e481051fa0e62807e518c5768e62dd.tar.xz | |
powerpc/uprobes: Implement arch_uretprobe_is_alive()
This helper is used to detect if a uprobe'd function has returned
through a setjmp/longjmp, rather than branching to the LR that was
updated previously by us. This fixes a SIGSEGV that gets generated when
programs use setjmp/longjmp with uretprobes.
We use the arm64 model (arch/arm64/kernel/probes/uprobes.c:
arch_uretprobe_is_alive()) for detecting when stack frames have been
removed from under us.
Reference:
https://marc.info/?l=linux-kernel&m=143748610330073
commit 7b868e4802a86 ("uprobes/x86: Reimplement arch_uretprobe_is_alive()")
commit db087ef69a2b1 ("uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more
clever")
Tested with the test program from:
https://sourceware.org/git/gitweb.cgi?p=systemtap.git;a=blob;f=testsuite/systemtap.base/bz5274.c;hb=HEAD
And this script:
$ cat test.sh
#!/bin/bash
perf probe -x ./bz5274 -a bz5274_main_return=main%return
perf probe -x ./bz5274 -a bz5274_funca_return=funca%return
perf probe -x ./bz5274 -a bz5274_funcb_return=funcb%return
perf probe -x ./bz5274 -a bz5274_funcc_return=funcc%return
perf probe -x ./bz5274 -a bz5274_funcd_return=funcd%return
perf record -e 'probe_bz5274:*' -aR ./bz5274
Reported-by: Gustavo Luiz Duarte <gduarte@redhat.com>
Reported-by: zsun@redhat.com
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/uprobes.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c index 003b20964ea0..5d105b8eeece 100644 --- a/arch/powerpc/kernel/uprobes.c +++ b/arch/powerpc/kernel/uprobes.c @@ -205,3 +205,12 @@ arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs return orig_ret_vaddr; } + +bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, + struct pt_regs *regs) +{ + if (ctx == RP_CHECK_CHAIN_CALL) + return regs->gpr[1] <= ret->stack; + else + return regs->gpr[1] < ret->stack; +} |