| Message ID | 1666866213-4394-1-git-send-email-wangyufen@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [net] bpf: Fix memory leaks in __check_func_call | expand |
Hi Wang,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on net/master]
url: https://github.com/intel-lab-lkp/linux/commits/Wang-Yufen/bpf-Fix-memory-leaks-in-__check_func_call/20221027-180438
patch link: https://lore.kernel.org/r/1666866213-4394-1-git-send-email-wangyufen%40huawei.com
patch subject: [PATCH net] bpf: Fix memory leaks in __check_func_call
config: i386-randconfig-a013
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/7e03dd8c129a0dbd7c32fb0931ad52e2c9a52f55
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Wang-Yufen/bpf-Fix-memory-leaks-in-__check_func_call/20221027-180438
git checkout 7e03dd8c129a0dbd7c32fb0931ad52e2c9a52f55
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash kernel/bpf/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> kernel/bpf/verifier.c:7003:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (!callee->in_callback_fn) {
^~~~~~~~~~~~~~~~~~~~~~~
kernel/bpf/verifier.c:7021:9: note: uninitialized use occurs here
return ret;
^~~
kernel/bpf/verifier.c:7003:2: note: remove the 'if' if its condition is always true
if (!callee->in_callback_fn) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/bpf/verifier.c:6962:9: note: initialize the variable 'ret' to silence this warning
int ret;
^
= 0
1 warning generated.
vim +7003 kernel/bpf/verifier.c
20571567384428 David Vernet 2022-09-19 6956
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6957 static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6958 {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6959 struct bpf_verifier_state *state = env->cur_state;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6960 struct bpf_func_state *caller, *callee;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6961 struct bpf_reg_state *r0;
7e03dd8c129a0d Wang Yufen 2022-10-27 6962 int ret;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6963
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6964 callee = state->frame[state->curframe];
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6965 r0 = &callee->regs[BPF_REG_0];
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6966 if (r0->type == PTR_TO_STACK) {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6967 /* technically it's ok to return caller's stack pointer
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6968 * (or caller's caller's pointer) back to the caller,
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6969 * since these pointers are valid. Only current stack
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6970 * pointer will be invalid as soon as function exits,
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6971 * but let's be conservative
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6972 */
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6973 verbose(env, "cannot return stack pointer to the caller\n");
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6974 return -EINVAL;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6975 }
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6976
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6977 state->curframe--;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6978 caller = state->frame[state->curframe];
69c087ba6225b5 Yonghong Song 2021-02-26 6979 if (callee->in_callback_fn) {
69c087ba6225b5 Yonghong Song 2021-02-26 6980 /* enforce R0 return value range [0, 1]. */
1bfe26fb082724 Dave Marchevsky 2022-09-08 6981 struct tnum range = callee->callback_ret_range;
69c087ba6225b5 Yonghong Song 2021-02-26 6982
69c087ba6225b5 Yonghong Song 2021-02-26 6983 if (r0->type != SCALAR_VALUE) {
69c087ba6225b5 Yonghong Song 2021-02-26 6984 verbose(env, "R0 not a scalar value\n");
7e03dd8c129a0d Wang Yufen 2022-10-27 6985 ret = -EACCES;
7e03dd8c129a0d Wang Yufen 2022-10-27 6986 goto out;
69c087ba6225b5 Yonghong Song 2021-02-26 6987 }
69c087ba6225b5 Yonghong Song 2021-02-26 6988 if (!tnum_in(range, r0->var_off)) {
69c087ba6225b5 Yonghong Song 2021-02-26 6989 verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
7e03dd8c129a0d Wang Yufen 2022-10-27 6990 ret = -EINVAL;
7e03dd8c129a0d Wang Yufen 2022-10-27 6991 goto out;
69c087ba6225b5 Yonghong Song 2021-02-26 6992 }
69c087ba6225b5 Yonghong Song 2021-02-26 6993 } else {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6994 /* return to the caller whatever r0 had in the callee */
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6995 caller->regs[BPF_REG_0] = *r0;
69c087ba6225b5 Yonghong Song 2021-02-26 6996 }
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6997
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 6998 /* callback_fn frame should have released its own additions to parent's
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 6999 * reference state at this point, or check_reference_leak would
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7000 * complain, hence it must be the same as the caller. There is no need
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7001 * to copy it back.
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7002 */
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 @7003 if (!callee->in_callback_fn) {
fd978bf7fd3125 Joe Stringer 2018-10-02 7004 /* Transfer references to the caller */
7e03dd8c129a0d Wang Yufen 2022-10-27 7005 ret = copy_reference_state(caller, callee);
7e03dd8c129a0d Wang Yufen 2022-10-27 7006 if (ret)
7e03dd8c129a0d Wang Yufen 2022-10-27 7007 goto out;
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7008 }
fd978bf7fd3125 Joe Stringer 2018-10-02 7009
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7010 *insn_idx = callee->callsite + 1;
06ee7115b0d174 Alexei Starovoitov 2019-04-01 7011 if (env->log.level & BPF_LOG_LEVEL) {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7012 verbose(env, "returning from callee:\n");
0f55f9ed21f966 Christy Lee 2021-12-16 7013 print_verifier_state(env, callee, true);
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7014 verbose(env, "to caller at %d:\n", *insn_idx);
0f55f9ed21f966 Christy Lee 2021-12-16 7015 print_verifier_state(env, caller, true);
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7016 }
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7017 /* clear everything in the callee */
7e03dd8c129a0d Wang Yufen 2022-10-27 7018 out:
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7019 free_func_state(callee);
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7020 state->frame[state->curframe + 1] = NULL;
7e03dd8c129a0d Wang Yufen 2022-10-27 7021 return ret;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7022 }
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7023
On Thu, Oct 27, 2022 at 3:03 AM Wang Yufen <wangyufen@huawei.com> wrote: > > kmemleak reports this issue: > > unreferenced object 0xffff88817139d000 (size 2048): > comm "test_progs", pid 33246, jiffies 4307381979 (age 45851.820s) > hex dump (first 32 bytes): > 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<0000000045f075f0>] kmalloc_trace+0x27/0xa0 > [<0000000098b7c90a>] __check_func_call+0x316/0x1230 > [<00000000b4c3c403>] check_helper_call+0x172e/0x4700 > [<00000000aa3875b7>] do_check+0x21d8/0x45e0 > [<000000001147357b>] do_check_common+0x767/0xaf0 > [<00000000b5a595b4>] bpf_check+0x43e3/0x5bc0 > [<0000000011e391b1>] bpf_prog_load+0xf26/0x1940 > [<0000000007f765c0>] __sys_bpf+0xd2c/0x3650 > [<00000000839815d6>] __x64_sys_bpf+0x75/0xc0 > [<00000000946ee250>] do_syscall_64+0x3b/0x90 > [<0000000000506b7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > The root case here is: In function prepare_func_exit(), the callee is > not released in the abnormal scenario after "state->curframe--;". > > In addition, function __check_func_call() has a similar problem. In > the abnormal scenario before "state->curframe++;", the callee is alse > not released. For prepare_func_exit, wouldn't it be correct and cleaner to just move state->curframe--; to the very bottom of the function, right when we free callee and reset frame[] pointer to NULL? For __check_func_call, please use err_out label name to disambiguate it from the "err" variable. > > Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") > Fixes: fd978bf7fd31 ("bpf: Add reference tracking to verifier") > Signed-off-by: Wang Yufen <wangyufen@huawei.com> > --- > kernel/bpf/verifier.c | 25 ++++++++++++++++--------- > 1 file changed, 16 insertions(+), 9 deletions(-) > [...]
在 2022/10/28 4:34, Andrii Nakryiko 写道: > On Thu, Oct 27, 2022 at 3:03 AM Wang Yufen <wangyufen@huawei.com> wrote: >> kmemleak reports this issue: >> >> unreferenced object 0xffff88817139d000 (size 2048): >> comm "test_progs", pid 33246, jiffies 4307381979 (age 45851.820s) >> hex dump (first 32 bytes): >> 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> backtrace: >> [<0000000045f075f0>] kmalloc_trace+0x27/0xa0 >> [<0000000098b7c90a>] __check_func_call+0x316/0x1230 >> [<00000000b4c3c403>] check_helper_call+0x172e/0x4700 >> [<00000000aa3875b7>] do_check+0x21d8/0x45e0 >> [<000000001147357b>] do_check_common+0x767/0xaf0 >> [<00000000b5a595b4>] bpf_check+0x43e3/0x5bc0 >> [<0000000011e391b1>] bpf_prog_load+0xf26/0x1940 >> [<0000000007f765c0>] __sys_bpf+0xd2c/0x3650 >> [<00000000839815d6>] __x64_sys_bpf+0x75/0xc0 >> [<00000000946ee250>] do_syscall_64+0x3b/0x90 >> [<0000000000506b7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd >> >> The root case here is: In function prepare_func_exit(), the callee is >> not released in the abnormal scenario after "state->curframe--;". >> >> In addition, function __check_func_call() has a similar problem. In >> the abnormal scenario before "state->curframe++;", the callee is alse >> not released. > For prepare_func_exit, wouldn't it be correct and cleaner to just move > state->curframe--; to the very bottom of the function, right when we > free callee and reset frame[] pointer to NULL? Yes, that't better. will change and test in v2. > For __check_func_call, please use err_out label name to disambiguate > it from the "err" variable. I got it. will change in v2. > >> Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") >> Fixes: fd978bf7fd31 ("bpf: Add reference tracking to verifier") >> Signed-off-by: Wang Yufen <wangyufen@huawei.com> >> --- >> kernel/bpf/verifier.c | 25 ++++++++++++++++--------- >> 1 file changed, 16 insertions(+), 9 deletions(-) >> > [...]
Hi Wang,
url: https://github.com/intel-lab-lkp/linux/commits/Wang-Yufen/bpf-Fix-memory-leaks-in-__check_func_call/20221027-180438
patch link: https://lore.kernel.org/r/1666866213-4394-1-git-send-email-wangyufen%40huawei.com
patch subject: [PATCH net] bpf: Fix memory leaks in __check_func_call
config: openrisc-randconfig-m031-20221026
compiler: or1k-linux-gcc (GCC) 12.1.0
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
smatch warnings:
kernel/bpf/verifier.c:7021 prepare_func_exit() error: uninitialized symbol 'ret'.
vim +/ret +7021 kernel/bpf/verifier.c
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6957 static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6958 {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6959 struct bpf_verifier_state *state = env->cur_state;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6960 struct bpf_func_state *caller, *callee;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6961 struct bpf_reg_state *r0;
7e03dd8c129a0d Wang Yufen 2022-10-27 6962 int ret;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6963
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6964 callee = state->frame[state->curframe];
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6965 r0 = &callee->regs[BPF_REG_0];
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6966 if (r0->type == PTR_TO_STACK) {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6967 /* technically it's ok to return caller's stack pointer
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6968 * (or caller's caller's pointer) back to the caller,
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6969 * since these pointers are valid. Only current stack
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6970 * pointer will be invalid as soon as function exits,
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6971 * but let's be conservative
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6972 */
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6973 verbose(env, "cannot return stack pointer to the caller\n");
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6974 return -EINVAL;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6975 }
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6976
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6977 state->curframe--;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6978 caller = state->frame[state->curframe];
69c087ba6225b5 Yonghong Song 2021-02-26 6979 if (callee->in_callback_fn) {
69c087ba6225b5 Yonghong Song 2021-02-26 6980 /* enforce R0 return value range [0, 1]. */
1bfe26fb082724 Dave Marchevsky 2022-09-08 6981 struct tnum range = callee->callback_ret_range;
69c087ba6225b5 Yonghong Song 2021-02-26 6982
69c087ba6225b5 Yonghong Song 2021-02-26 6983 if (r0->type != SCALAR_VALUE) {
69c087ba6225b5 Yonghong Song 2021-02-26 6984 verbose(env, "R0 not a scalar value\n");
7e03dd8c129a0d Wang Yufen 2022-10-27 6985 ret = -EACCES;
7e03dd8c129a0d Wang Yufen 2022-10-27 6986 goto out;
69c087ba6225b5 Yonghong Song 2021-02-26 6987 }
69c087ba6225b5 Yonghong Song 2021-02-26 6988 if (!tnum_in(range, r0->var_off)) {
69c087ba6225b5 Yonghong Song 2021-02-26 6989 verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
7e03dd8c129a0d Wang Yufen 2022-10-27 6990 ret = -EINVAL;
7e03dd8c129a0d Wang Yufen 2022-10-27 6991 goto out;
69c087ba6225b5 Yonghong Song 2021-02-26 6992 }
69c087ba6225b5 Yonghong Song 2021-02-26 6993 } else {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6994 /* return to the caller whatever r0 had in the callee */
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6995 caller->regs[BPF_REG_0] = *r0;
69c087ba6225b5 Yonghong Song 2021-02-26 6996 }
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 6997
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 6998 /* callback_fn frame should have released its own additions to parent's
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 6999 * reference state at this point, or check_reference_leak would
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7000 * complain, hence it must be the same as the caller. There is no need
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7001 * to copy it back.
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7002 */
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7003 if (!callee->in_callback_fn) {
fd978bf7fd3125 Joe Stringer 2018-10-02 7004 /* Transfer references to the caller */
7e03dd8c129a0d Wang Yufen 2022-10-27 7005 ret = copy_reference_state(caller, callee);
7e03dd8c129a0d Wang Yufen 2022-10-27 7006 if (ret)
7e03dd8c129a0d Wang Yufen 2022-10-27 7007 goto out;
9d9d00ac29d0ef Kumar Kartikeya Dwivedi 2022-08-23 7008 }
Not initialized on else path.
fd978bf7fd3125 Joe Stringer 2018-10-02 7009
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7010 *insn_idx = callee->callsite + 1;
06ee7115b0d174 Alexei Starovoitov 2019-04-01 7011 if (env->log.level & BPF_LOG_LEVEL) {
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7012 verbose(env, "returning from callee:\n");
0f55f9ed21f966 Christy Lee 2021-12-16 7013 print_verifier_state(env, callee, true);
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7014 verbose(env, "to caller at %d:\n", *insn_idx);
0f55f9ed21f966 Christy Lee 2021-12-16 7015 print_verifier_state(env, caller, true);
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7016 }
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7017 /* clear everything in the callee */
7e03dd8c129a0d Wang Yufen 2022-10-27 7018 out:
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7019 free_func_state(callee);
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7020 state->frame[state->curframe + 1] = NULL;
7e03dd8c129a0d Wang Yufen 2022-10-27 @7021 return ret;
f4d7e40a5b7157 Alexei Starovoitov 2017-12-14 7022 }
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 014ee09..bff8477 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6736,11 +6736,11 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn /* Transfer references to the callee */ err = copy_reference_state(callee, caller); if (err) - return err; + goto err; err = set_callee_state_cb(env, caller, callee, *insn_idx); if (err) - return err; + goto err; clear_caller_saved_regs(env, caller->regs); @@ -6757,6 +6757,10 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn print_verifier_state(env, callee, true); } return 0; + +err: + kfree(callee); + return err; } int map_set_for_each_callback_args(struct bpf_verifier_env *env, @@ -6954,7 +6958,7 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) struct bpf_verifier_state *state = env->cur_state; struct bpf_func_state *caller, *callee; struct bpf_reg_state *r0; - int err; + int ret; callee = state->frame[state->curframe]; r0 = &callee->regs[BPF_REG_0]; @@ -6977,11 +6981,13 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) if (r0->type != SCALAR_VALUE) { verbose(env, "R0 not a scalar value\n"); - return -EACCES; + ret = -EACCES; + goto out; } if (!tnum_in(range, r0->var_off)) { verbose_invalid_scalar(env, r0, &range, "callback return", "R0"); - return -EINVAL; + ret = -EINVAL; + goto out; } } else { /* return to the caller whatever r0 had in the callee */ @@ -6995,9 +7001,9 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) */ if (!callee->in_callback_fn) { /* Transfer references to the caller */ - err = copy_reference_state(caller, callee); - if (err) - return err; + ret = copy_reference_state(caller, callee); + if (ret) + goto out; } *insn_idx = callee->callsite + 1; @@ -7008,9 +7014,10 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) print_verifier_state(env, caller, true); } /* clear everything in the callee */ +out: free_func_state(callee); state->frame[state->curframe + 1] = NULL; - return 0; + return ret; } static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
kmemleak reports this issue: unreferenced object 0xffff88817139d000 (size 2048): comm "test_progs", pid 33246, jiffies 4307381979 (age 45851.820s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<0000000045f075f0>] kmalloc_trace+0x27/0xa0 [<0000000098b7c90a>] __check_func_call+0x316/0x1230 [<00000000b4c3c403>] check_helper_call+0x172e/0x4700 [<00000000aa3875b7>] do_check+0x21d8/0x45e0 [<000000001147357b>] do_check_common+0x767/0xaf0 [<00000000b5a595b4>] bpf_check+0x43e3/0x5bc0 [<0000000011e391b1>] bpf_prog_load+0xf26/0x1940 [<0000000007f765c0>] __sys_bpf+0xd2c/0x3650 [<00000000839815d6>] __x64_sys_bpf+0x75/0xc0 [<00000000946ee250>] do_syscall_64+0x3b/0x90 [<0000000000506b7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd The root case here is: In function prepare_func_exit(), the callee is not released in the abnormal scenario after "state->curframe--;". In addition, function __check_func_call() has a similar problem. In the abnormal scenario before "state->curframe++;", the callee is alse not released. Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") Fixes: fd978bf7fd31 ("bpf: Add reference tracking to verifier") Signed-off-by: Wang Yufen <wangyufen@huawei.com> --- kernel/bpf/verifier.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-)