Remove the check that rejects sleepable BPF programs from doing BPF_ANY/BPF_EXIST updates on local storage. This restriction was added in commit b00fa38a9c1c ("bpf: Enable non-atomic allocations in local storage") because kzalloc(GFP_KERNEL) could sleep inside local_storage->lock. This is no longer a concern: all local storage allocations now use kmalloc_nolock() which never sleeps. In addition, since kmalloc_nolock() only accepts __GFP_ACCOUNT, __GFP_ZERO and __GFP_NO_OBJ_EXT, the gfp_flags parameter plumbing from bpf_*_storage_get() to bpf_local_storage_update() becomes dead code. Remove gfp_flags from bpf_selem_alloc(), bpf_local_storage_alloc() and bpf_local_storage_update(). Drop the hidden 5th argument from bpf_*_storage_get helpers, and remove the verifier patching that injected GFP_KERNEL/GFP_ATOMIC into the fifth argument. Signed-off-by: Amery Hung --- include/linux/bpf_local_storage.h | 7 +++---- kernel/bpf/bpf_cgrp_storage.c | 9 ++++----- kernel/bpf/bpf_inode_storage.c | 9 ++++----- kernel/bpf/bpf_local_storage.c | 16 ++++++---------- kernel/bpf/bpf_task_storage.c | 9 ++++----- kernel/bpf/verifier.c | 26 -------------------------- net/core/bpf_sk_storage.c | 17 +++++++---------- 7 files changed, 28 insertions(+), 65 deletions(-) diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index dced54e9265f..9e4f5c45c974 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -188,7 +188,7 @@ int bpf_selem_link_map(struct bpf_local_storage_map *smap, struct bpf_local_storage_elem * bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value, - bool swap_uptrs, gfp_t gfp_flags); + bool swap_uptrs); void bpf_selem_free(struct bpf_local_storage_elem *selem, bool reuse_now); @@ -196,12 +196,11 @@ void bpf_selem_free(struct bpf_local_storage_elem *selem, int bpf_local_storage_alloc(void *owner, struct bpf_local_storage_map *smap, - struct bpf_local_storage_elem *first_selem, - gfp_t gfp_flags); + struct bpf_local_storage_elem *first_selem); struct bpf_local_storage_data * bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, - void *value, u64 map_flags, bool swap_uptrs, gfp_t gfp_flags); + void *value, u64 map_flags, bool swap_uptrs); u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map); diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c index d93ac2866748..c76e9b0fabba 100644 --- a/kernel/bpf/bpf_cgrp_storage.c +++ b/kernel/bpf/bpf_cgrp_storage.c @@ -76,7 +76,7 @@ static long bpf_cgrp_storage_update_elem(struct bpf_map *map, void *key, return PTR_ERR(cgroup); sdata = bpf_local_storage_update(cgroup, (struct bpf_local_storage_map *)map, - value, map_flags, false, GFP_ATOMIC); + value, map_flags, false); cgroup_put(cgroup); return PTR_ERR_OR_ZERO(sdata); } @@ -122,9 +122,8 @@ static void cgroup_storage_map_free(struct bpf_map *map) bpf_local_storage_map_free(map, &cgroup_cache); } -/* *gfp_flags* is a hidden argument provided by the verifier */ -BPF_CALL_5(bpf_cgrp_storage_get, struct bpf_map *, map, struct cgroup *, cgroup, - void *, value, u64, flags, gfp_t, gfp_flags) +BPF_CALL_4(bpf_cgrp_storage_get, struct bpf_map *, map, struct cgroup *, cgroup, + void *, value, u64, flags) { struct bpf_local_storage_data *sdata; @@ -143,7 +142,7 @@ BPF_CALL_5(bpf_cgrp_storage_get, struct bpf_map *, map, struct cgroup *, cgroup, if (!percpu_ref_is_dying(&cgroup->self.refcnt) && (flags & BPF_LOCAL_STORAGE_GET_F_CREATE)) sdata = bpf_local_storage_update(cgroup, (struct bpf_local_storage_map *)map, - value, BPF_NOEXIST, false, gfp_flags); + value, BPF_NOEXIST, false); out: return IS_ERR_OR_NULL(sdata) ? (unsigned long)NULL : (unsigned long)sdata->data; diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c index efc8996a4c0a..0da8d923e39d 100644 --- a/kernel/bpf/bpf_inode_storage.c +++ b/kernel/bpf/bpf_inode_storage.c @@ -98,7 +98,7 @@ static long bpf_fd_inode_storage_update_elem(struct bpf_map *map, void *key, sdata = bpf_local_storage_update(file_inode(fd_file(f)), (struct bpf_local_storage_map *)map, - value, map_flags, false, GFP_ATOMIC); + value, map_flags, false); return PTR_ERR_OR_ZERO(sdata); } @@ -122,9 +122,8 @@ static long bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key) return inode_storage_delete(file_inode(fd_file(f)), map); } -/* *gfp_flags* is a hidden argument provided by the verifier */ -BPF_CALL_5(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode, - void *, value, u64, flags, gfp_t, gfp_flags) +BPF_CALL_4(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode, + void *, value, u64, flags) { struct bpf_local_storage_data *sdata; @@ -150,7 +149,7 @@ BPF_CALL_5(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode, if (flags & BPF_LOCAL_STORAGE_GET_F_CREATE) { sdata = bpf_local_storage_update( inode, (struct bpf_local_storage_map *)map, value, - BPF_NOEXIST, false, gfp_flags); + BPF_NOEXIST, false); return IS_ERR(sdata) ? (unsigned long)NULL : (unsigned long)sdata->data; } diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index d0e6070fa68c..77bb1b76fd4b 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -68,7 +68,7 @@ static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem) struct bpf_local_storage_elem * bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, - void *value, bool swap_uptrs, gfp_t gfp_flags) + void *value, bool swap_uptrs) { struct bpf_local_storage_elem *selem; @@ -464,8 +464,7 @@ static int check_flags(const struct bpf_local_storage_data *old_sdata, int bpf_local_storage_alloc(void *owner, struct bpf_local_storage_map *smap, - struct bpf_local_storage_elem *first_selem, - gfp_t gfp_flags) + struct bpf_local_storage_elem *first_selem) { struct bpf_local_storage *prev_storage, *storage; struct bpf_local_storage **owner_storage_ptr; @@ -535,7 +534,7 @@ int bpf_local_storage_alloc(void *owner, */ struct bpf_local_storage_data * bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, - void *value, u64 map_flags, bool swap_uptrs, gfp_t gfp_flags) + void *value, u64 map_flags, bool swap_uptrs) { struct bpf_local_storage_data *old_sdata = NULL; struct bpf_local_storage_elem *alloc_selem, *selem = NULL; @@ -552,9 +551,6 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, !btf_record_has_field(smap->map.record, BPF_SPIN_LOCK))) return ERR_PTR(-EINVAL); - if (gfp_flags == GFP_KERNEL && (map_flags & ~BPF_F_LOCK) != BPF_NOEXIST) - return ERR_PTR(-EINVAL); - local_storage = rcu_dereference_check(*owner_storage(smap, owner), bpf_rcu_lock_held()); if (!local_storage || hlist_empty(&local_storage->list)) { @@ -563,11 +559,11 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, if (err) return ERR_PTR(err); - selem = bpf_selem_alloc(smap, owner, value, swap_uptrs, gfp_flags); + selem = bpf_selem_alloc(smap, owner, value, swap_uptrs); if (!selem) return ERR_PTR(-ENOMEM); - err = bpf_local_storage_alloc(owner, smap, selem, gfp_flags); + err = bpf_local_storage_alloc(owner, smap, selem); if (err) { bpf_selem_free(selem, true); mem_uncharge(smap, owner, smap->elem_size); @@ -597,7 +593,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, /* A lookup has just been done before and concluded a new selem is * needed. The chance of an unnecessary alloc is unlikely. */ - alloc_selem = selem = bpf_selem_alloc(smap, owner, value, swap_uptrs, gfp_flags); + alloc_selem = selem = bpf_selem_alloc(smap, owner, value, swap_uptrs); if (!alloc_selem) return ERR_PTR(-ENOMEM); diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index 55f4f22bb212..4b342be29eac 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -118,7 +118,7 @@ static long bpf_pid_task_storage_update_elem(struct bpf_map *map, void *key, sdata = bpf_local_storage_update( task, (struct bpf_local_storage_map *)map, value, map_flags, - true, GFP_ATOMIC); + true); err = PTR_ERR_OR_ZERO(sdata); out: @@ -165,9 +165,8 @@ static long bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key) return err; } -/* *gfp_flags* is a hidden argument provided by the verifier */ -BPF_CALL_5(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *, - task, void *, value, u64, flags, gfp_t, gfp_flags) +BPF_CALL_4(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *, + task, void *, value, u64, flags) { struct bpf_local_storage_data *sdata; @@ -184,7 +183,7 @@ BPF_CALL_5(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *, (flags & BPF_LOCAL_STORAGE_GET_F_CREATE)) { sdata = bpf_local_storage_update( task, (struct bpf_local_storage_map *)map, value, - BPF_NOEXIST, false, gfp_flags); + BPF_NOEXIST, false); return IS_ERR(sdata) ? (unsigned long)NULL : (unsigned long)sdata->data; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7aa06f534cb2..0d2218033fdb 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -603,14 +603,6 @@ static bool is_may_goto_insn_at(struct bpf_verifier_env *env, int insn_idx) return is_may_goto_insn(&env->prog->insnsi[insn_idx]); } -static bool is_storage_get_function(enum bpf_func_id func_id) -{ - return func_id == BPF_FUNC_sk_storage_get || - func_id == BPF_FUNC_inode_storage_get || - func_id == BPF_FUNC_task_storage_get || - func_id == BPF_FUNC_cgrp_storage_get; -} - static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id, const struct bpf_map *map) { @@ -23893,24 +23885,6 @@ static int do_misc_fixups(struct bpf_verifier_env *env) goto patch_call_imm; } - if (is_storage_get_function(insn->imm)) { - if (env->insn_aux_data[i + delta].non_sleepable) - insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC); - else - insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL); - insn_buf[1] = *insn; - cnt = 2; - - new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); - if (!new_prog) - return -ENOMEM; - - delta += cnt - 1; - env->prog = prog = new_prog; - insn = new_prog->insnsi + i + delta; - goto patch_call_imm; - } - /* bpf_per_cpu_ptr() and bpf_this_cpu_ptr() */ if (env->insn_aux_data[i + delta].call_with_percpu_alloc_ptr) { /* patch with 'r1 = *(u64 *)(r1 + 0)' since for percpu data, diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 9fb22e352beb..3aaaf21c00eb 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -106,7 +106,7 @@ static long bpf_fd_sk_storage_update_elem(struct bpf_map *map, void *key, if (sock) { sdata = bpf_local_storage_update( sock->sk, (struct bpf_local_storage_map *)map, value, - map_flags, false, GFP_ATOMIC); + map_flags, false); sockfd_put(sock); return PTR_ERR_OR_ZERO(sdata); } @@ -227,9 +227,8 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk) return ret; } -/* *gfp_flags* is a hidden argument provided by the verifier */ -BPF_CALL_5(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk, - void *, value, u64, flags, gfp_t, gfp_flags) +BPF_CALL_4(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk, + void *, value, u64, flags) { struct bpf_local_storage_data *sdata; @@ -250,7 +249,7 @@ BPF_CALL_5(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk, refcount_inc_not_zero(&sk->sk_refcnt)) { sdata = bpf_local_storage_update( sk, (struct bpf_local_storage_map *)map, value, - BPF_NOEXIST, false, gfp_flags); + BPF_NOEXIST, false); /* sk must be a fullsock (guaranteed by verifier), * so sock_gen_put() is unnecessary. */ @@ -383,16 +382,14 @@ static bool bpf_sk_storage_tracing_allowed(const struct bpf_prog *prog) return false; } -/* *gfp_flags* is a hidden argument provided by the verifier */ -BPF_CALL_5(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk, - void *, value, u64, flags, gfp_t, gfp_flags) +BPF_CALL_4(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk, + void *, value, u64, flags) { WARN_ON_ONCE(!bpf_rcu_lock_held()); if (in_hardirq() || in_nmi()) return (unsigned long)NULL; - return (unsigned long)____bpf_sk_storage_get(map, sk, value, flags, - gfp_flags); + return (unsigned long)____bpf_sk_storage_get(map, sk, value, flags); } BPF_CALL_2(bpf_sk_storage_delete_tracing, struct bpf_map *, map, -- 2.52.0