Since commit 85e031154c7c ("powerpc/bpf: Perform complete extra passes to update addresses"), two additional passes are performed to avoid space and CPU time wastage on powerpc. But these extra passes led to WARN_ON_ONCE() hits in bpf_add_extable_entry() as extable entries are populated again, during the extra pass, without resetting the index. Fix it by resetting entry index before repopulating extable entries, if and when there is an additional pass.
Fixes: 85e031154c7c ("powerpc/bpf: Perform complete extra passes to update addresses") Cc: stable@vger.kernel.org Signed-off-by: Hari Bathini hbathini@linux.ibm.com --- arch/powerpc/net/bpf_jit_comp.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index e93aefcfb83f..37043dfc1add 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -101,6 +101,8 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) bpf_hdr = jit_data->header; proglen = jit_data->proglen; extra_pass = true; + /* During extra pass, ensure index is reset before repopulating extable entries */ + cgctx.exentry_idx = 0; goto skip_init_ctx; }
Hari Bathini wrote:
Since commit 85e031154c7c ("powerpc/bpf: Perform complete extra passes to update addresses"), two additional passes are performed to avoid space and CPU time wastage on powerpc. But these extra passes led to WARN_ON_ONCE() hits in bpf_add_extable_entry() as extable entries are populated again, during the extra pass, without resetting the index. Fix it by resetting entry index before repopulating extable entries, if and when there is an additional pass.
Fixes: 85e031154c7c ("powerpc/bpf: Perform complete extra passes to update addresses") Cc: stable@vger.kernel.org Signed-off-by: Hari Bathini hbathini@linux.ibm.com
arch/powerpc/net/bpf_jit_comp.c | 2 ++ 1 file changed, 2 insertions(+)
Reviewed-by: Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com
- Naveen
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index e93aefcfb83f..37043dfc1add 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -101,6 +101,8 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) bpf_hdr = jit_data->header; proglen = jit_data->proglen; extra_pass = true;
/* During extra pass, ensure index is reset before repopulating extable entries */
goto skip_init_ctx; }cgctx.exentry_idx = 0;
2.40.0
On Tue, 25 Apr 2023 12:28:29 +0530, Hari Bathini wrote:
Since commit 85e031154c7c ("powerpc/bpf: Perform complete extra passes to update addresses"), two additional passes are performed to avoid space and CPU time wastage on powerpc. But these extra passes led to WARN_ON_ONCE() hits in bpf_add_extable_entry() as extable entries are populated again, during the extra pass, without resetting the index. Fix it by resetting entry index before repopulating extable entries, if and when there is an additional pass.
[...]
Applied to powerpc/fixes.
[1/1] powerpc/bpf: populate extable entries only during the last pass https://git.kernel.org/powerpc/c/35a4b8ce4ac00e940b46b1034916ccb22ce9bdef
cheers
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